Israel-Hamas war latest: A cease-fire is key to ending the region's cycle of violence, Blinken says

U.S. Secretary of State Antony Blinken appealed for “all parties” in the Middle East to avoid escalatory actions that could plunge the region into further conflict, and said Thursday that a cease-fire between Israel and Hamas was the only way to begin to break the cycle of violence and suffering.

The remarks came as prayers were held by Iran’s Supreme Leader Ayatollah Ali Khamenei and representatives of Palestinian militia groups for Hamas leader Ismail Haniyeh and his bodyguard. Worry has spread that Wednesday's shock assassination risks escalating the fighting into an all-out regional war.

No one immediately claimed responsibility for the attack, but suspicion quickly fell on Israel, which has vowed to kill Haniyeh and other Hamas leaders over the group’s Oct. 7 attack on Israel that sparked the war.

The assassination of Haniyeh in Tehran and the strike against senior Hezbollah commander Fouad Shukur in Beirut could upend the attempts to defuse a Middle East powder keg, with Iran also threatening to respond after the attack on its territory. And the Israeli military said Thursday it confirmed that the head of Hamas’ military wing, Mohammed Deif, was killed in an airstrike in Gaza in July.

During a late-July visit to the U.S., Israeli Prime Minister Benjamin Netanyahu said his country was determined to win nothing less than “total victory” against Hamas. Asked directly by journalists on the point later, he said that Israel hoped for a cease-fire soon and was working for one.

Here’s the latest:

JOINT BASE ANDREWS, Maryland — President Joe Biden said late Thursday he’s “very concerned” that the violence in the Middle East could escalate, adding that the killing of a top Hamas leader in Iran has “not helped” efforts to negotiate a cease-fire in Israel’s war with Gaza.

Biden said he’d had a “very direct” conversation with Israeli Prime Minister Benjamin Netanyahu earlier in the day, repeating “very direct” for emphasis.

He added: “We have the basis for a cease-fire. He should move on it and they should move on it now.”

Biden spoke on the tarmac of an air base outside Washington after welcoming back to the United States three Americans who were freed in a prisoner swap earlier in the day.

WASHINGTON — President Joe Biden spoke Thursday afternoon with Israeli Prime Minister Benjamin Netanyahu, with the White House saying in a readout that Biden “reaffirmed his commitment to Israel’s security against all threats from Iran, including its proxy terrorist groups Hamas, Hezbollah and the Houthis.” Vice President Kamala Harris also participated in the call.

Biden also discussed efforts to support Israel’s defense and the importance of reducing tensions in the region, officials said.

The U.S. president discussed with Netanyahu new U.S. military deployments to protect against possible attacks from ballistic missiles and drones. In April, U.S. forces intercepted dozens of missiles and drones fired by Iran against Israel and helped down nearly all of them.

The conversation comes as U.S., Egyptian and Qatari mediators are scrambling to salvage talks in the wake of back-to-back killings of Hamas’ top political leader in Iran and a Hezbollah commander in Lebanon. Those killings have increased fears of an escalation into a wider war, leaving the region waiting to see how Iran and ally Hezbollah will respond.

BEIRUT — Lebanon’s Health Ministry says an Israeli airstrike on a southern village has killed four people and wounded five.

The ministry said the four killed in Thursday’s airstrike on the village of Chamaa were Syrian citizens. It said five Lebanese citizens were wounded in the same airstrike.

The leader of the militant Hezbollah group said in a speech Thursday that his fighters had stopped carrying out attacks along the border following an Israeli airstrike on Beirut on Tuesday that killed a top military commander with the group.

Hezbollah later said that it fired dozens of Katyusha rockets toward the Matzuva kibbutz in northern Israel in retaliation for the airstrike.

Hassan Nasrallah said Hezbollah will resume attacks on Friday but this will not be part of the retaliation that the group plans to carry for the death of commander Fouad Shukur.

Israel said the strike that killed Shukur was in retaliation for a rocket attack on Saturday that killed 12 young people in the town of Majdal Shams in Syria’s Israeli-occupied Golan Heights. Nasrallah on Thursday repeated the group’s denials that it fired the rocket that struck Majdal Shams.

In the thousands of rockets it has fired since October, Hezbollah has insisted it targets military and intelligence installations. Hezbollah says it only fires on civilian areas when civilians are killed or wounded in Lebanon. Before Saturdays bloodshed in Majdal Shams, its strikes had killed 13 civilians and 22 soldiers in Israel. In Lebanon. Israel’s attacks have killed more than 500 people, including 90 civilians.

JERUSALEM — The leader of Yemen’s Houthi rebels said Thursday that efforts were underway to militarily respond to Israel following the killings of senior Hamas and Hezbollah leaders that have raised the prospect of war in the region.

The leader of the militant group, Abdul-Malek al-Houthi, said in a televised speech that “there must be a military response to the serious crimes and the significant escalation by the Israeli enemy.” “Efforts are underway to respond,” he added.

The speech came after Israel killed top Hezbollah commander Fouad Shukur in Beirut and the assassination in Iran of Hamas’ political leader, Ismail Haniyeh, earlier this week. The region is bracing for a potential conflagration following the two killings.

JERUSALEM — Israel’s military has claimed a Palestinian reporter for Al Jazeera killed in an airstrike targeting his vehicle in the Gaza Strip on Wednesday was a Hamas militant, without providing evidence.

The military said Al Jazeera correspondent Ismail al-Ghoul “was actively involved in recording and publicizing attacks against IDF troops” and “instructed other operatives on how to record operations.” It described al-Ghoul’s work as “a vital part of Hamas’ military activity.”

The army statement Thursday said nothing about camera operator Rami al-Rifi, who was killed alongside al-Ghoul in the Israeli strike that hit their car near Shati camp in northern Gaza, where they had been reporting from the birthplace of slain Hamas political chief, Ismail Haniyeh.

The military also said that al-Ghoul participated in Hamas’ October 7th attack on Israel, without elaborating or offering proof. Hamas did not respond to Israel’s claim Thursday.

Al Jazeera, the influential Qatar-based satellite network, vehemently denied the Israeli military’s allegations about al-Ghoul, calling them “completely false.”

“Al Jazeera rejects the claim and the lies and considers them a blatant attempt to justify targeting journalists in Gaza,” said Walid Omary, the Al Jazeera bureau chief based in the occupied West Bank city of Ramallah.

.The network on Wednesday accused Israel of deliberately targeting its reporters and vowed to “pursue all legal actions to prosecute the perpetrators of these crimes”.

The Committee to Protect Journalists has said the war in Gaza has led to the deadliest period for reporters since it began gathering data in 1992, with at least 111 journalists and media workers killed in Gaza.

SHUJAIYA, Gaza Strip — Israeli airstrikes on a school sheltering displaced Palestinians in the eastern Gaza City district of Shujaiya killed at least 15 people and wounded more than 40 others, the Palestinian Civil Defense reported.

The Israeli army said that Hamas fighters used the compound “as a hideout for commanders and operatives” to plot attacks against Israel.

Schools crowded with displaced families in Gaza have been targeted throughout the war by the Israeli army, which says that Hamas uses civilian infrastructure as bases for military operations.

JERUSALEM — Israel’s National Security Council is warning Israeli travelers to exercise extra caution abroad, citing fears that Israeli or Jewish institutions might be targeted by Iran-allied militants. The warning Thursday comes as tensions escalate over Israel’s assassinations of Hamas political leader Ismail Haniyeh in Tehran and influential Hezbollah commander Fouad Shukur in Beirut.

Iran’s leaders have vowed revenge for Haniyeh’s killing, which was considered one of the most embarrassing breaches of Iran’s defenses in years. International alarm has grown over the possibility of an all-out regional conflict.

Israeli authorities said that Iran’s regional proxies could seek retaliation through attacks on embassies, synagogues, Israeli businesses and other sites around the world and urged Israeli travelers to avoid demonstrations and remain vigilant in public places. The security council also warned Israelis against wearing symbols that make them identifiable as Jews.

BEIRUT — In the southern suburbs of the Lebanese capital, hundreds of black-clad mourners packed an auditorium Thursday for the funeral procession of Hezbollah commander Fouad Shukur, killed in an Israeli strike in Beirut this week.

Many of them held Hezbollah flags or photos of Shukur. An escort of red-capped fighters carried Shukur’s coffin, also draped in a Hezbollah flag, down the aisle to the backing of a military band.

An unusual calm prevailed Thursday on the Lebanon-Israel border, where exchanges of rockets and shelling have become a daily occurrence. Hezbollah claimed no rocket launches into Israel during the day.

It and Iran have been mulling their response to the killings of Shukur and of Hamas political leader Ismail Haniyeh in a suspected Israeli strike in Tehran on Wednesday,

The killings have triggered fears of a cycle of escalation that could spark a regional war that has been narrowly avoided over the past 10 months.

TEHRAN, Iran — Iran’s Revolutionary Guard said Thursday that an Iranian military adviser died in the Israeli airstrike in Beirut earlier in the week that killed a senior Hezbollah commander.

In a statement on its website, the Guard identified the adviser as Milad Bidi, saying he had been operating in Syria and Lebanon. The Guard has advisers in both countries working with key allies Hezbollah, the Syrian government and other militias.

The Guard did not specify the day of the strike that killed Bidi, but Tuesday evening’s attack was the only Israeli strike hit in the Lebanese capital since January. The strike hit a building in a Beirut suburb, killing a Hezbollah commander Fouad Shukur, along with at least five civilians.

The Beirut strike and an alleged Israeli airstrike in Tehran that killed Hamas’ top political leader Ismail Haniyeh on Wednesday have hiked fears of an expanded regional war. Shukur’s funeral was set to take place Thursday in Beirut.

SINGAPORE — Singapore is deeply concerned about developments in the Middle East, including the killing of Haniyeh, who was involved in negotiations for a cease-fire in Gaza, the government said Thursday.

“This puts at risk efforts to secure a cease-fire agreement that would allow for the release of all hostages and facilitate humanitarian assistance to the civilian population,” the Foreign Ministry said in a statement.

Singapore called on all parties to take steps to de-escalate tensions to avoid a wider regional conflagration.

JERUSALEM — The Israeli military said Thursday that it has confirmed that the head of Hamas’ military wing, Mohammed Deif, was killed in an airstrike in Gaza in July.

Israel targeted Deif in a July 13 strike that hit a compound on the outskirts of the southern Gaza city of Khan Younis, but the military said for weeks it was working to determine if he died in the blast. Hamas has denied he was killed. More than 90 other people, including displaced civilians in nearby tents, were killed in the strike, Gaza health officials said at the time.

In a statement Thursday, the Israeli military said that “following an intelligence assessment, it can be confirmed that Mohammed Deif was eliminated in the strike.”

There was no immediate comment from Hamas.

NICOSIA, Cyprus — An American container carrier ship is making trips from Cyprus to the Israeli port of Ashdod every few days to deliver at least another 2,200 tons of donated humanitarian aid that’s intended for Palestinians in war-torn Gaza.

The United States decided in July to dismantle its military-built pier carrying the aid directly to the Palestinian territory, but in the meantime, Israeli officials remain on hand at the Cypriot port to monitor screening procedures that employ large, arc-shaped X-Ray machines through which pallet-laden trucks pass.

So far, nearly 10,000 tons of humanitarian aid — about 80% of which is food — have reached Gaza through the maritime link and officials are looking ahead to help in eventual reconstruction efforts once a firm cease-fire is in place.

The U.S.-headquartered charity World Central Kitchen made the first direct Cyprus-Gaza trip as part of the maritime corridor initiative on March 12 with the Open Arms ship that towed a barge loaded with aid pallets to a makeshift jetty.

TEHRAN, Iran — In his speech at Haniyeh’s funeral ceremony in Tehran, Parliament Speaker Mohammad Bagher Qalibaf said that such attacks are carried out under the United States’ guidance and coordination, “and nothing happens without the coordination and support of criminal America.”

State TV broadcast Qalibaf’s speech live as he insisted that the U.S. had a role in Haniyeh’s assassination, and accused Washington of lying that it had not been informed of any plans for the attack.

Thousands of people in Tehran attended the Haniyeh’s funeral, waving Iranian, Palestinian, and Hezbollah flags.

State TV showed people on the street mostly wearing black dresses representing sadness, in temperatures already reaching 33 degrees Celsius (91.4 degrees Fahrenheit) at 11 a.m. local time. A giant mist sprayer was deployed to make the hot temperature cooler for the people. The coffins could be seen being placed in a truck and moved on the street toward Azadi, “Freedom” in Farsi, Square in Tehran, with people throwing flowers at them.

ISTANBUL — Thousands of people marched in central Istanbul to protest the assassination of Hamas political leader Ismail Haniyeh.

Carrying Palestinian flags and photographs of Haniyeh, the protesters gathered outside Fatih Mosque late Wednesday, marched through the historic district of Fatih, and performed funeral prayers for the Hamas chief.

“Let’s not let the blood of the children there be shed anymore, we say enough is enough. Let’s go there. Let’s fight,” said Veysel Orhan, one of the protesters.

Turkish President Recep Tayyip Erdogan, who has been one of Israel’s most vocal critics, has denounced Haniyeh’s killing as a “despicable act” and vowed to continue supporting the Palestinian cause “with all our means and strength.”

ULAANBAATAR, Mongolia — United States Secretary of State Antony Blinken says “all parties” in the Middle East must avoid escalatory actions that could plunge the region into further conflict following the assassination of Hamas’ political leader in Tehran that Hamas and Iran have blamed on Israel.

Speaking in the Mongolian capital of Ulaanbaatar on Thursday, Blinken appealed for countries to “make the right choices in the days ahead” and said that a cease-fire between Israel and Hamas in Gaza was the only way to begin to break the current cycle of violence and suffering. Blinken did not mention Israel, Iran or Hamas by name in his comments.

“Right now, the path that the region is on is toward more conflict, more violence, more suffering, more insecurity and it is crucial that we break the cycle and that starts with the cease-fire that we’ve been working on, which I believe is not only achievable, it has to be achieved,” Blinken said.

Blinken noted that even while in Asia he has been on the phone with regional leaders, including the prime minister of Qatar and the foreign minister of Jordan.

“We’re all focused on making sure we can get the cease-fire over the finish line and building on it for everyone’s sake, for the future,” he said.

BEIRUT — Iran’s supreme leader and representatives of Palestinian militias he backs prayed Thursday over the coffins of Hamas leader Ismail Haniyeh and his bodyguard, who were killed in a shocking assassination blamed on Israel that risked escalating into an all-out regional war.

Ayatollah Ali Khamenei prayed over Haniyeh’s coffin at Tehran University while Iran’s new President Masoud Pezeshkian stood next to him. State television later showed the coffins placed in a truck and moved on the street toward Azadi Square in Tehran, with people throwing flowers at them.

After the funeral services in Tehran, Haniyeh’s remains are to be transferred to Qatar for burial Friday.

Haniyeh came to Tehran to attend Pezeshkian's inauguration. Associated Press photos showed the Hamas leader seated alongside leaders from the Palestinian Islamic Jihad militant group and Hezbollah, and Iranian media showed him and Pezeshkian hugging. Haniyeh had met earlier with Khamenei.

SYDNEY — Australia’s Prime Minister Anthony Albanese urged thousands of Australian citizens in Lebanon to leave and warned Thursday that the Beirut airport could soon close.

“I take the opportunity to say to Australians: Do not travel to Lebanon at the moment,” Albanese told reporters in Sydney.

“There is a risk that the Beirut airport might not be open for commercial flights and given the numbers of people who are there, there’s no guarantee that we can just guarantee that people will be able to come home through other means if that airport is shut.”

Albanese said he was “very concerned” that conflict in the Middle East would escalate following the killing of Hamas leader Ismail Haniyeh in Iran.

“We want to see a de-escalation, we want to see a cease-fire, we want to see the hostages released and we want to see a plan for peace and security in the Middle East where both Israelis and Palestinians can live in peace and security with prosperity,” Albanese said.

U.S. Secretary of State Antony Blinken speaks during a joint press conference with Mongolia's Foreign Minister Batmunkh Battsetseg, unseen, in Ulaanbaatar, Mongolia Thursday, Aug. 1, 2024. (AP Photo/Munkhbayar Magvandorj)

Hezbollah fighters stand behind the coffin of their top commander Fouad Shukur, who was killed by an Israeli airstrike on Tuesday, July 30, as Hezbollah leader Sayyed Hassan Nasrallah speaks through a screen during Shukur's funeral in a southern suburb of Beirut, Lebanon, Aug. 1, 2024. (AP Photo/Hussein Malla)

Iranian protesters wave Iranian, Palestinian and Lebanon's militant Hezbollah group flags in a demonstration to condemn the killing of Hamas leader Ismail Haniyeh as a huge portrait of him is seen on a wall at background, at Felestin (Palestine) Sq. in Tehran, Iran, Wednesday, July 31, 2024. Two back-to-back strikes in Beirut and Tehran, both attributed to Israel and targeting high-ranking figures in Hezbollah and Hamas, have left Hezbollah and Iran in a quandary. (AP Photo/Vahid Salemi)

In this photo released by the official website of the office of the Iranian supreme leader, Supreme Leader Ayatollah Ali Khamenei, third right, leads a prayer over the coffins of Hamas leader Ismail Haniyeh and his bodyguard who were killed in an assassination blamed on Israel on Wednesday, during their funeral ceremony at the Tehran University campus, in Tehran, Iran, Thursday, Aug. 1, 2024. Iranian President Masoud Pezeshkian prays at second right. (Office of the Iranian Supreme Leader via AP)

Hezbollah fighters stand behind the coffin of their top commander Fouad Shukur, who was killed by an Israeli airstrike on Tuesday, July 30, as Hezbollah leader Sayyed Hassan Nasrallah speaks through a screen during Shukur's funeral in a southern suburb of Beirut, Lebanon, Aug. 1, 2024. (AP Photo/Hussein Malla)

In this photo released by the office of the Iranian supreme leader, Supreme Leader Ayatollah Ali Khamenei, right, speaks with Hamas chief Ismail Haniyeh, center, and the leader of the Palestinian Islamic Jihad group Ziad Nakhaleh in their meeting in Tehran, Iran, Tuesday, July 30, 2024. A portrait of the late Iranian revolutionary founder Ayatollah Khomeini hangs on the wall. (Office of the Iranian Supreme Leader via AP)

Iranians follow a truck, center, carrying the coffins of Hamas leader Ismail Haniyeh and his bodyguard who were killed in an assassination blamed on Israel on Wednesday, during their funeral ceremony at Enqelab-e-Eslami (Islamic Revolution) Sq. in Tehran, Iran, Thursday, Aug. 1, 2024. (AP Photo/Vahid Salemi)

An Iranian woman, carrying a Palestinian flag, walks to attend the funeral ceremony of Hamas leader Ismail Haniyeh and his bodyguard, at Enqelab-e-Eslami (Islamic Revolution) Sq. in Tehran, Iran, Thursday, Aug. 1, 2024. (AP Photo/Vahid Salemi)

Iranians attend the funeral ceremony of Hamas leader Ismail Haniyeh and his bodyguard, some of them holding up posters with his photo and reading in Arabic: "Congratulations Haniyeh!" at Enqelab-e-Eslami (Islamic Revolution) Sq. in Tehran, Iran, Thursday, Aug. 1, 2024. (AP Photo/Vahid Salemi)

Hezbollah fighters carry the coffin of their top commander Fouad Shukur, who was killed by an Israeli airstrike on Tuesday, July 30, during his funeral procession in a southern suburb of Beirut, Lebanon, Aug. 1, 2024. (AP Photo/Hussein Malla)

Iranians follow a truck, center, carrying the coffins of Hamas leader Ismail Haniyeh and his bodyguard who were killed in an assassination blamed on Israel on Wednesday, during their funeral ceremony at Enqelab-e-Eslami (Islamic Revolution) Sq. in Tehran, Iran, Thursday, Aug. 1, 2024. (AP Photo/Vahid Salemi)

An Iranian woman holds a poster of Hamas leader Ismail Haniyeh with Arabic writing: "Congratulations Haniyeh!" during his funeral ceremony and of his bodyguard, after they were killed on Wednesday in an assassination blamed on Israel, at Enqelab-e-Eslami (Islamic Revolution) Sq. in Tehran, Iran, Thursday, Aug. 1, 2024. (AP Photo/Vahid Salemi)

In this photo released by the official website of the office of the Iranian supreme leader, people carry the coffin of Hamas leader Ismail Haniyeh who was killed in an assassination blamed on Israel on Wednesday, during his funeral ceremony at the Tehran University campus, in Tehran, Iran, Thursday, Aug. 1, 2024. (Office of the Iranian Supreme Leader via AP)

Hezbollah fighters stand behind the coffin of their top commander Fouad Shukur, who was killed by an Israeli airstrike on Tuesday, July 30, during his funeral procession in a southern suburb of Beirut, Lebanon, Aug. 1, 2024. (AP Photo/Hussein Malla)

A Palestinian man walks through a shopping street in the West Bank city of Nablus, where shops are closed, following the assassination of Hamas leader Ismail Haniyeh, Wednesday, July 31, 2024. (AP Photo/Majdi Mohammed)

Supporters of the Pakistani religious group "Jamaat-e-Islami" hold a poster of Hamas leader Ismail Haniyeh during a protest to condemn his killing, in Hyderabad, Pakistan, Wednesday, July 31, 2024. Haniyeh was assassinated in Tehran, Iran's paramilitary Revolutionary Guard said early Wednesday. (AP Photo/Pervez Masih)

FILE - Mourners from the Druze minority surround the bodies of some of the 12 children and teens killed in a rocket strike at a soccer field, in the village of Majdal Shams at the Israeli-controlled Golan Heights, Sunday, July 28, 2024. Two back-to-back strikes in Beirut and Tehran, both attributed to Israel and targeting high-ranking figures in Hezbollah and Hamas, have left Hezbollah and Iran in a quandary. (AP Photo/Leo Correa, File)

Members of Tehran University Council attend a protest to condemn the killing of Hamas political chief Ismail Haniyeh as they carry Iranian and Palestinian flags while they walk on a representation of the Israeli flag at the University, in Tehran, Iran, Wednesday, July 31, 2024. Haniyeh, Hamas' political chief in exile was killed in an airstrike in the Iranian capital early Wednesday. (AP Photo/Vahid Salemi)

A supporter of the Islamist Hamas movement carries her son, who holds a machine gun toy during a protest in the southern port city of Sidon, Lebanon, Wednesday, July 31, 2024, to condemn the killing of Hamas political chief Ismail Haniyeh. Two back-to-back strikes in Beirut and Tehran, both attributed to Israel and targeting high-ranking figures in Hezbollah and Hamas, have left Hezbollah and Iran in a quandary. (AP Photo/Mohammed Zaatari)

In this photo released by the office of the Iranian supreme leader, Supreme Leader Ayatollah Ali Khamenei, right, speaks with Hamas chief Ismail Haniyeh, center, and the leader of the Palestinian Islamic Jihad group Ziad Nakhaleh in their meeting in Tehran, Iran, Tuesday, July 30, 2024. A portrait of the late Iranian revolutionary founder Ayatollah Khomeini hangs on the wall. (Office of the Iranian Supreme Leader via AP)

Supporters of the Pakistani religious group "Jamaat-e-Islami" offer the Absent funeral prayer for Hamas leader Ismail Haniyeh, in Hyderabad, Pakistan, Wednesday, July 31, 2024. Haniyeh was assassinated in Tehran, Iran's paramilitary Revolutionary Guard said early Wednesday. (AP Photo/Pervez Masih)

U.S. Secretary of State Antony Blinken speaks during a conversation on Advancing Security and Prosperity in the Indo-Pacific Region with Singapore's Ambassador-at-Large Chan Heng Chee at the Asian Civilisations Museum in Singapore, Wednesday, July 31, 2024. (AP Photo/Suhaimi Abdullah)

People visit the site of a rocket strike that killed twelve children and teens at a soccer field in the village of Majdal Shams, in the Israeli-annexed Golan Heights, Thursday, Aug. 1, 2024. (AP Photo/Leo Correa)

A young woman reacts during a protest to condemn the killing of Hamas political chief Ismail Haniyeh, at al-Bass Palestinian refugee camp, in the southern port city of Tyre, Lebanon, Wednesday, July 31, 2024. Haniyeh, Hamas' political chief in exile who landed on Israel's hit list after the militant group staged its surprise Oct. 7 attacks, was killed in an airstrike in the Iranian capital early Wednesday. (AP Photo/Mohammed Zaatari)

Iranian protesters hold posters of the Supreme Leader Ayatollah Ali Khamenei in a demonstration to condemn killing of Hamas leader Ismail Haniyeh, at Felestin Sq. in Tehran, Iran, Wednesday, July 31, 2024. Haniyeh was assassinated in Tehran, Iran's paramilitary Revolutionary Guard said early Wednesday. (AP Photo/Vahid Salemi)

STOCKHOLM (AP) — The Nobel Prize in physiology or medicine was awarded Monday to Americans Victor Ambros and Gary Ruvkun for their discovery of microRNA, tiny pieces of genetic material that alter how genes work at the cellular level and could lead to new ways of treating cancer.

The Nobel Assembly at the Karolinska Institute, which awarded the prize, said the duo's discovery is “proving to be fundamentally important" in understanding how organisms develop and function.

MicroRNA have opened up scientists’ approaches to treating diseases like cancer by helping to regulate how genes work at the cellular level, according to Dr. Claire Fletcher, a lecturer in molecular oncology at Imperial College London.

Fletcher said microRNA provide genetic instructions to tell cells to make new proteins and that there were two main areas where microRNA could be helpful: in developing drugs to treat diseases and in serving as biomarkers.

“MicroRNA alters how genes in the cell work,” said Fletcher, who is an outside expert not associated with the Nobel prize.

“If we take the example of cancer, we’ll have a particular gene working overtime, it might be mutated and working in overdrive,” she said. “We can take a microRNA that we know alters the activity of that gene and we can deliver that particular microRNA to cancer cells to stop that mutated gene from having its effect.”

Ambros performed the research that led to his prize at Harvard University. He is currently a professor of natural science at the University of Massachusetts Medical School. Ruvkun's research was performed at Massachusetts General Hospital and the Harvard Medical School, where he’s a professor of genetics, said Thomas Perlmann, Secretary-General of the Nobel Committee.

Perlmann said he spoke to Ruvkun by phone shortly before the announcement.

“It took a long time before he came to the phone and sounded very tired, but he quite rapidly was quite excited and happy, when he understood what it was all about,” Perlmann said.

Last year, the Nobel Prize in Physiology or Medicine went to Hungarian-American Katalin Karikó and American Drew Weissman for discoveries that enabled the creation of mRNA vaccines against COVID-19 that were critical in slowing the pandemic.

The prize carries a cash award of 11 million Swedish kronor ($1 million) from a bequest left by the prize’s creator, Swedish inventor Alfred Nobel.

The announcement launched this year’s Nobel prizes award season.

Nobel announcements continue with the physics prize on Tuesday, chemistry on Wednesday and literature on Thursday. The Nobel Peace Prize will be announced Friday and the Nobel Memorial Prize in Economic Sciences on Oct. 14.

The laureates are invited to receive their awards at ceremonies on Dec. 10, the anniversary of Nobel’s death.

Fletcher said there are clinical trials ongoing to see how microRNA approaches might help treat skin cancer, but that there aren’t yet any drug treatments approved by drug regulators. She expected that might happen in the next five to 10 years.

She said microRNA represent another way of being able to control the behaviour of genes to treat and track various diseases.

“The majority of therapies we have at the moment are targeting proteins in cells,” she said. “If we can intervene at the microRNA level, it opens up a whole new way of us developing medicines and us controlling the activity of genes whose levels might be altered in diseases.”

Corder reported from The Hague, Netherlands, Cheng reported from London.

This undated picture released by Mass General shows American molecular biologist Gary Ruvkun. (Joshua Touster via AP)

This undated picture released by UMass shows Victor Ambros, PhD, the Silverman Chair in Natural Sciences and professor of molecular medicine. (UMass via AP)

Olle Kämpe, right, professor of clinical endocrinology, explains the work of this year's Nobel Prize in Physiology or Medicine laureates Americans Victor Ambros, and Gary Ruvkun during a press conference at the Karolinska Institute in Stockholm, Sweden, on Monday, Oct. 7, 2024. (Christine Olsson/TT News Agency via AP)

Olle Kämpe, right, professor of clinical endocrinology, explains the work of this year's Nobel Prize in Physiology or Medicine laureates Americans Victor Ambros, and Gary Ruvkun, pictured on the screen, during a press conference at the Karolinska Institute in Stockholm, Sweden, on Monday, Oct. 7, 2024. (Christine Olsson/TT News Agency via AP)

Americans Victor Ambros, left, and Gary Ruvkun, are seen on a screen after being awarded this year's Nobel Prize in Physiology or Medicine during a press conference to announce the winners at the Karolinska Institute in Stockholm, Sweden, on Monday, Oct. 7, 2024. (Christine Olsson/TT News Agency via AP)

Nobel Committee chairman Thomas Perlmann, right, announces Americans Victor Ambros, left, and Gary Ruvkun, seen on a screen being awarded this year's Nobel Prize in Physiology or Medicine, during a press conference at the Karolinska Institute in Stockholm, Sweden, on Monday, Oct. 7, 2024. (Christine Olsson/TT News Agency via AP)

FILE - A close-up view of a Nobel Prize medal at the National Institutes of Health (NIH) in Bethesda, Md., Tuesday, Dec. 8, 2020. (AP Photo/Jacquelyn Martin, File)

FILE - A bust of Alfred Nobel on display following a press conference at the Karolinska Institute in Stockholm, Sweden, on Monday, Oct. 3, 2022. (Henrik Montgomery/TT News Agency via AP, File)