U.N. experts say the interference of Chadian and Sudanese fighters in Libya is “a direct threat” to the security and stability of the war-torn country, which a leader of the Islamic State extremist group has declared “one of the main axes” of its future operations.

The panel of experts said in a 376-page report to the U.N. Security Council released Tuesday that the presence of the Chadians and Sudanese “has become more marked” in 2019 as a result of the intensification of the conflict in Libya. It said their continued presence as organized groups or as mercenaries “may lead to further instability.”

Libya has been in turmoil since a civil war in 2011 toppled Moammar Gadhafi, who was later killed. In the chaos that followed, the country was divided, with a weak U.N.-supported administration in Tripoli overseeing the country's west and a rival government in the east aligned with the Libyan National Army led by Gen. Khalifa Hifter, each supported by an array of militias and foreign governments.

Hifter launched a surprise military offensive April 4 aimed at capturing Tripoli despite commitments to attend a national conference weeks later aimed at forming a united government and moving toward elections. Fighting for Tripoli has stalled in recent months, with both sides dug in and shelling one another along the city’s southern reaches with increasingly sophisticated weapons.

While the LNA and the eastern government enjoy the support of France, Russia, Jordan, the United Arab Emirates and other key Arab countries, the Tripoli-based government is backed by Italy, Turkey and Qatar.

"Jordan, Turkey and the United Arab Emirates routinely and sometimes blatantly supplied weapons, with little effort to disguise the source" in violation of a U.N. arms embargo, the report said.

The experts identified multiple cases of non-compliance with the arms embargo, the majority of transfers to Hifter’s LNA from Jordan or the United Arab Emirates and the majority to the Tripoli government from Turkey.

But, the panel said, "Neither side has the military capability to effectively decide the outcome to their advantage."

The experts said counter-terrorism operations in Libya against Islamic State and al-Qaida extremists by the government and Hifter’s forces, and an increase in activity by the United States Africa Command, continue to disrupt the structure of both groups and temporarily reduce their capacity to conduct operations.

But the panel also reported the new focus on Libya by the Islamic State, also known as ISIL, quoting a video in July by an Islamic State leader in Libya, Mahmud Massud al-Baraassi, also known as Abu Musab Allibi. In the video, the report said, “he highlighted that Libya was now one of the main axes of future ISIL operations, which are designed to compensate for the loss of ground” in Syria.

“ISIL in Libya finances its activities through robbery, kidnap for ransom, extortion of Libyan citizens and the cross-border smuggling of artifacts and other commodities,” the panel said. “Taxation of human trafficking networks continues to be a source of funding for ISIL in Libya.”

As for foreign fighters, the experts named five Sudanese armed groups operating in Libya — four in support of Hifter’s LNA and one backing the government’s forces. They named four Chadian armed groups — one supporting the LNA, two supporting the government, and one with 100 fighters whose factions support both side.

In one example, the panel estimated 1,000 Sudanese troops from Sudan's Rapid Support Forces were deployed to Libya on July 25 by Gen. Mohamed Hamdan Dagalo, initially to guard critical infrastructure so Hifter’s troops could carry out offensive operations.

The panel said Sudan and Dagalo, who has command responsibility, both violated U.N. sanctions.

The Associated Press reported last week that Libyan government officials plan to confront Moscow over the alleged deployment of Russian mercenaries fighting alongside Hifter’s LNA. U.S. officials also accuse Russia of deploying fighters through a private security contractor to key battleground areas in Libya in the past months.

The U.N. panel of experts, who monitor sanctions against Libya, made no mention of Russian mercenaries in the report. Several diplomats said they expect the Russian mercenary issue to be raised in the Security Council.