The United States withdrew from a "hypocritical and self-serving" United Nations Human Rights Council on Tuesday over what it called chronic bias against Israel and a lack of reform.
Activists warned it would make advancing human rights globally even more difficult.
Standing with U.S. Secretary of State Mike Pompeo at the State Department, U.S. Ambassador to the United Nations Nikki Haley slammed Russia, China, Cuba and Egypt for thwarting U.S. efforts to reform the council.
She also criticized countries which shared U.S. values and encouraged Washington to remain, but "were unwilling to seriously challenge the status quo." Washington's withdrawal is the latest U.S. rejection of multilateral engagement after it pulled out of the Paris climate agreement and the 2015 Iran nuclear deal.
It also comes as the United States faces intense criticism for detaining children separated from their immigrant parents at the U.S.-Mexico border. U.N. human rights chief Zeid Ra'ad al-Hussein on Monday called on Washington to halt its "unconscionable" policy.
"Look at the council membership, and you see an appalling disrespect for the most basic rights," said Haley, citing Venezuela, China, Cuba and Democratic Republic of Congo. She did not mention Saudi Arabia, which rights groups pushed to be suspended in 2016 over killings of civilians in the Yemen war.
Among reforms the United States had pushed for was to make it easier to kick out member states with egregious rights records. Currently a two-thirds majority vote by the 193-member U.N. General Assembly is needed to suspend a member state.
Haley also said the "disproportionate focus and unending hostility toward Israel is clear proof that the council is motivated by political bias, not by human rights." Israeli Prime Minister Benjamin Netanyahu welcomed the U.S. decision.
The United States has long shielded its ally Israel at the United Nations.