Dozens of civilians, mostly children, were killed or injured in an airstrike on Thursday by U.S. allies on a bus in a crowded market in northern Yemen. The International Committee of the Red Cross said the attack struck a bus carrying children in ... Saada province, which borders Saudi Arabia. Body parts were scattered all over the area," said Hassan Muwlef, executive director of the Red Crescent office in Saada. "The school bus was totally burned and destroyed." Most of the children were under the age of 10, [said] Johannes Bruwer, the ICRC's head of delegation in Yemen. The assault was the latest airstrike against civilians carried out by an American-backed regional coalition led by Saudi Arabia and the United Arab Emirates. The coalition entered Yemen's civil war more than three years ago to fight northern Houthi rebels, who seized power from Yemen's internationally recognized government. The conflict has also turned into a proxy war ... between the Sunni Muslim coalition and Iran's Shiite theocracy, which is widely believed to be backing the rebels. The United States is helping the coalition, the only party in the conflict to use warplanes, with refueling, intelligence and billions in weapons sales. Human rights groups and Washington Post journalists have seen remnants of U.S.-made bombs at attack sites where civilians were struck. Civilian deaths have continued to multiply, even as the coalition promises not to target civilians.