UNITED NATIONS (Reuters) - A Saudi Arabia-led military coalition has carried out attacks in Yemen that “may amount to war crimes,” U.N. sanctions monitors reported to the world body’s Security Council, warning coalition allies including the United States, Britain and France that they are obligated to respect international humanitarian law.

Pro-Houthi fighters, who have been injured during recent fighting, shout slogans during a rally held to honour those injured or maimed while fighting in Houthi ranks in Sanaa, Yemen, January 29, 2017. REUTERS/Mohamed al-Sayaghi

The annual report by the experts who monitor sanctions and the conflict in Yemen, seen by Reuters on Saturday, investigated 10 coalition air strikes between March and October that killed at least 292 civilians, including some 100 women and children.

“In eight of the 10 investigations, the panel found no evidence that the air strikes had targeted legitimate military objectives,” the experts wrote in a 63-page report presented to the Security Council on Friday.

“For all 10 investigations, the panel considers it almost certain that the coalition did not meet international humanitarian law requirements of proportionality and precautions in attack,” the report said. “The panel considers that some of the attacks may amount to war crimes.”

The experts said Saudi Arabia is leading a military coalition made up of Bahrain, Kuwait, Qatar, the United Arab Emirates, Egypt, Jordan, Morocco and Sudan.

Saudi U.N. Ambassador Abdallah Al-Mouallimi said the accusations in the report were unfounded, that the coalition has been “exercising maximum restraint and rigorous rules of engagement,” and that there had been transparent investigations into any incidents.

“In some cases errors were acknowledged and responsibility accepted. Corrective measures including compensation to victims were taken,” he told Reuters.

The U.N. experts said U.S. officers were supporting coalition logistical and intelligence activities, while the coalition’s chief of joint operations told the experts that officers from France, Malaysia and Britain were also present at the Riyadh headquarters.

“All coalition member states and their allies also have an obligation to take appropriate measures to ensure respect for international humanitarian law by the coalition,” the U.N. experts wrote.

“The panel finds that violations associated with the conduct of the air campaign are sufficiently widespread to reflect either an ineffective targeting process or a broader policy of attrition against civilian infrastructure,” the report said.

‘WIDESPREAD, SYSTEMATIC VIOLATIONS’

The U.N. experts said that although they were unable to travel to Yemen, they have “maintained the highest achievable standard of proof.”

A spokesman for the British U.N. mission declined to comment on a leaked document, but added: “We take reports of alleged violations of international humanitarian law by actors in the conflict very seriously.”

A senior U.S. State Department official said: “We urge all sides to take steps to prevent harm to civilians. Ending the conflict in Yemen requires a durable cessation of hostilities and a comprehensive political solution.”

The French Foreign Ministry and the Malaysian U.N. mission did not immediately respond to requests for comment. Malaysia has said that its armed forces are not involved in the Saudi-led campaign in Yemen. It said Malaysian troops in Saudi Arabia were only part of training exercise.

The outcry over civilian casualties has led some lawmakers and rights activists in the United States and Britain to push for curbs on arms sales to Riyadh.

The Saudi-led coalition began a military campaign in support of Yemeni government forces nearly two years ago to prevent Houthi rebels, whom it sees as a proxy for Iran, from taking complete control of Yemen after seizing much of the north.

The Houthis, who are allied with forces loyal to former Yemen president Ali Abdullah Saleh, deny carrying out any crimes in their war effort and say they are defending the country and its civilians from Saudi-led foreign “aggression.””There have also been widespread and systematic violations of international humanitarian law, international human rights law and human rights norms by officials and security forces affiliated (with) the (Yemen) government and (with) the Houthis,” the U.N. report said.

The U.N. experts said it was “highly likely that the Houthi and Saleh forces did not comply with international humanitarian law in at least three incidents when they fired explosive ordnance at a market, a house and a hospital.”

Yemen and Saudi Arabia blame Iran for supplying weapons to the Houthis, but Tehran denies that. The U.N. experts said they had identified 2,064 weapons seized from boats off Yemen that “could be directly linked to Iranian manufacture of origin.”

“The panel has not seen sufficient evidence to confirm any direct large-scale supply of arms from the Government of the Islamic Republic of Iran, although there are indicators that anti-tank guided weapons being supplied to the Houthi or Saleh forces are of Iranian manufacture,” the experts said.

Iran’s mission to the United Nations did not immediately respond to a request for comment.