Amnesty International called Wednesday for a "suspension" in transfers of certain arms to members of a Saudi-led coalition battling Yemeni rebels following "damning evidence of war crimes".
The London-based watchdog urged holding an "independent, effective investigation of violations" by the coalition, in which US allies the United Arab Emirates and Saudi Arabia are playing a key role.
Amnesty's latest report "uncovers yet more evidence of unlawful airstrikes carried out by the Saudi Arabia-led coalition, some of which amount to war crimes," said Donatella Rovera, who headed the group's fact-finding mission to Yemen.
"It demonstrates in harrowing detail how crucial it is to stop arms being used to commit serious violations of this kind," she said.
The report, titled "'Bombs fall from the sky day and night’: Civilians under fire in northern Yemen" focuses on the plight of civilians in the rebel Shiite Huthi strongholds.
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It "examines 13 deadly airstrikes by the coalition in Saada... which killed some 100 civilians, including 59 children", said Amnesty of the report, which also documents the use of "internationally banned cluster bombs".
"The USA and other states exporting weapons to any of the parties to the Yemen conflict have a responsibility to ensure that the arms transfers they authorise are not facilitating serious violations of international humanitarian law," said Amnesty.
It said that transfers of arms and munitions used by members of the Saudi-led coalition to "commit violations of international humanitarian law, including war crimes in Yemen" must be suspended.
Amnesty specified "bombs from the MK (MARK) 80 series and other general purpose bombs, fighter jets, combat helicopters and their associated parts and components".
Since March, Saudi Arabia has been leading a coalition of Sunni Arab countries battling the Iran-backed rebels who seized the capital Sanaa last year before moving south to take more territory.
Rights groups have repeatedly accused the coalition of causing civilian casualties during their bombing campaign.
The United Nations says the Yemeni conflict has killed about 5,000 people and wounded 25,000, among them many civilians.