Amnesty International said Thursday that a Saudi-led coalition had bombed schools in Yemen, violating international humanitarian law and denying access to education for thousands of children.
The London-based rights group called on "all states who supply arms to the Saudi Arabia-led coalition, including the USA and UK, to suspend all transfers of weapons which are being used to commit violations of international law".
Riyadh and its allies launched air strikes in Yemen in late March to support forces loyal to President Abd-rabbo Mansour Hadi after Iran-backed Shiite Huthi rebels overran much of the country.
Rights watchdogs have accused the coalition of breaking the laws of war and killing civilians, but it has repeatedly denied targeting them.
In a report titled "Our kids are bombed", Amnesty said it investigated five air strikes on schools between August and October, killing five civilians and injuring at least 14, including four children.
"In some cases the schools were struck more than once, suggesting the strikes were deliberately targeted," the group said.
Students were not inside the schools during the attacks, but the strikes caused serious damage that has disrupted the education of more than 6,500 children in Hajja, Hodeida and Sanaa provinces, it said.
"No evidence could be found in any of the five cases to suggest the schools had been used for military purposes," it added.
Lama Fakih, senior crisis advisor at Amnesty, said: "Schools are central to civilian life, they are meant to offer a safe space for children.
"It is simply appalling that the USA and other allies of the Saudi Arabia-led coalition have continued to authorise arms transfers to members of the coalition," she said.
In November, Washington approved a $1.29-billion deal to replenish the Saudi air force's arsenal.
The order included 6,300 Paveway II and Paveway III laser-guided bombs, 12,000 general purpose bombs weighing and 1,500 devastating "bunker busters" designed to smash hardened concrete structures.
The United Nations says more than 5,700 people have been killed in Yemen, about half of them civilians, since March when fighting intensified. More than 25,000 have been wounded.