In a damning report, the New York-based Human Rights Watch said that a disproportionate number of the victims were civilians and that remnants of munitions found at the site of the attack showed that they were American made, AP reported.
An international investigation is needed into the "atrocity," said Sarah Leah Whitson, Middle East director for the rights group.
The group also called for both the US and UK to immediately suspend all arms sales to Saudi Arabia. The two countries have sold the kingdom billions of dollars in weapons.
On Saturday, Saudi-led warplanes targeted a crowded funeral ceremony in Sana’a, killing over 140 people and injuring more than 600 others.
Since March 2015, Saudi Arabia and some of its Arab allies have been launching deadly airstrikes against the Houthi Ansarullah movement in an attempt to restore power to the fugitive former President Abd Rabbuh Mansour Hadi, a close ally of Riyadh.
According to UN estimates, over 10,000 Yemenis, including 4,000 women and children, have lost their lives in the military campaign.