The Latest on tensions in the Persian Gulf and the fallout after weekend attack on major oil sites in Saudi Arabia (all times local):

11:40 a.m.

Syrian opposition activists say unknown aircraft have attacked posts of Iranian-backed fighters in an eastern town near the Iraqi border.

This Saturday, Sept. 14, 2019, satellite image from Planet Labs Inc. shows thick black smoke rising from Saudi Aramco's Abqaiq oil processing facility in Buqyaq, Saudi Arabia. Yemen's Houthi rebels launched drone attacks on the world's largest oil processing facility in Saudi Arabia and a major oil field Saturday, sparking huge fires and halting about half of the supplies from the world's largest exporter of oil. (Planet Labs Inc via AP)

This Saturday, Sept. 14, 2019, satellite image from Planet Labs Inc. shows thick black smoke rising from Saudi Aramco's Abqaiq oil processing facility in Buqyaq, Saudi Arabia. Yemen's Houthi rebels launched drone attacks on the world's largest oil processing facility in Saudi Arabia and a major oil field Saturday, sparking huge fires and halting about half of the supplies from the world's largest exporter of oil. (Planet Labs Inc via AP)

The activists said the airstrike took place early Tuesday in Boukamal, in the eastern province of Deir el-Zour. There was no immediate word on casualties.

Last week in Syria, unknown warplanes targeted an arms depot and posts of Iranian-backed militias in Boukamal, killing at least 18 fighters. A Syrian security official said Israeli jets were behind the attack but denied there were casualties.

The Britain-based Syrian Observatory for Human Rights and Deir Ezzor 24, an activist collective, said the strikes occurred near the border crossing with Iraq. The opening of the crossing, planned by Iraq and Syria, had been postponed several times in recent weeks.

In this photo released by the official website of the office of the Iranian Presidency, President Hassan Rouhani heads a cabinet meeting in Tehran, Iran, Wednesday, Sept. 11, 2019. Rouhani urged the U.S. on Wednesday to "put warmongers aside" as tensions roil the Persian Gulf amid an escalating crisis between Washington and Tehran in the wake of the collapsing nuclear deal with world powers. (Iranian Presidency Office via AP)

In this photo released by the official website of the office of the Iranian Presidency, President Hassan Rouhani heads a cabinet meeting in Tehran, Iran, Wednesday, Sept. 11, 2019. Rouhani urged the U.S. on Wednesday to "put warmongers aside" as tensions roil the Persian Gulf amid an escalating crisis between Washington and Tehran in the wake of the collapsing nuclear deal with world powers. (Iranian Presidency Office via AP)

10:30 a.m.

Iran's Supreme Leader Ayatollah Ali Khamenei says "there will be no talks with the U.S. at any level" — remarks apparently meant to end all speculation about a U.S.-Iran meeting at the U.N. later this month.

Iranian state TV on Tuesday quotes Khamenei as saying this is the position of the entire leadership of the country and that "all officials in the Islamic Republic unanimously believe" this.

This Sunday, Sept. 15, 2019 false-color image from the European Commission's Sentinel-2 satellite shows Saudi Aramco's Abqaiq oil processing facility in Buqyaq, Saudi Arabia. Yemen's Houthi rebels claimed to have launched drone attacks on the world's largest oil processing facility in Saudi Arabia and a major oil field Saturday, sparking huge fires and halting about half of the supplies from the world's largest exporter of oil. Black char marks at the center of the facility suggest the attack struck at the heart of the processing facility (European Commission via AP)

This Sunday, Sept. 15, 2019 false-color image from the European Commission's Sentinel-2 satellite shows Saudi Aramco's Abqaiq oil processing facility in Buqyaq, Saudi Arabia. Yemen's Houthi rebels claimed to have launched drone attacks on the world's largest oil processing facility in Saudi Arabia and a major oil field Saturday, sparking huge fires and halting about half of the supplies from the world's largest exporter of oil. Black char marks at the center of the facility suggest the attack struck at the heart of the processing facility (European Commission via AP)

There has been speculation about a possible meeting between President Donald Trump and his Iranian counterpart, Hassan Rouhani, during the upcoming U.N. General Assembly this month in New York.

Tensions roiling the Persian Gulf have escalated following a weekend attack on major oil sites in Saudi Arabia that U.S. alleged Iran was responsible for. Iran denies the charge.