Human rights groups are demanding the United Nations reopen an investigation into atrocities committed in Yemen, after the U.N. Human Rights Council voted in October against extending an independent war crimes investigation. Dozens of organizations, including Human Rights Watch and Amnesty International, said in a joint statement Thursday that Saudi Arabia and the United Arab Emirates “bribed, coerced and arm-twisted” council members to win a 21-18 vote ordering an end to the war crimes probe, which was set up four years ago. Agnès Callamard, the secretary general of Amnesty International, said all parties to the conflict in Yemen — including Saudi and Houthi forces — have committed atrocities with impunity.

Agnès Callamard: “There is seemingly no end in sight for this war. There is no light that we can see at the end of the tunnel. For that reason, we have to act now, because every day that goes by … far more people are being harmed and killed. And, indeed, to say that a mechanism could save millions of lives is not an exaggeration.”

The U.N. estimates about a quarter of a million people have been killed as a result of Yemen’s war, with some 4 million Yemenis displaced since the U.S.-backed, Saudi-led coalition intervened in 2015.