An international human rights group says that the Saudi-led coalition's bombing of a packed funeral in the Yemeni capital, Sanaa, this week constitutes an apparent war crime and that the remnants of missiles found at the site of the attack showed that they were American made.

Human Rights Watch said Thursday that a disproportionate number of the victims were civilians when the coalition carried out two airstrikes on Saturday on the funeral, which top military and security officials had been expected to attend. Nearly 140 people were killed and over 600 were wounded.

An international investigation is needed into the "atrocity," said Sarah Leah Whitson, Middle East director for the rights group. She says the attack on the funeral joins a long list of abuses by the coalition.