The US has pulled out of the United Nations Human Rights Council, calling it a “cesspool of political bias”.
The “hypocritical and self-serving” body “makes a mockery of human rights”, said US envoy to the UN Nikki Haley.
Formed in 2006, the Geneva-based council has been criticised for allowing countries with questionable human rights records to be members.
But activists said the US move could hurt efforts to monitor and address human rights abuses around the world.
Ms Haley announced her country’s intention to quit the council at a joint news conference with Secretary of State Mike Pompeo, who called the council “a poor defender of human rights”.
UN Secretary-General António Guterres, in a statement released through his spokesman, responded by saying he would have “much preferred” the US to remain in the council.
The UN human rights commissioner, Zeid Ra’ad Al Hussein, called the US withdrawal “disappointing, if not really surprising, news”. Israel, meanwhile, has praised the decision.
"Disappointing, if not really surprising, news. Given the state of #HumanRights in today's world, the US should be stepping up, not stepping back" — UN Human Rights Chief #Zeid following USA decision to withdraw from U.N. Human Rights Council.#StandUp4HumanRights
— UN Human Rights (@UNHumanRights) June 19, 2018
The move comes amid intense criticism over the Trump administration’s policy of separating child migrants from their parents at the US-Mexico border.
On Monday Mr Hussein has called the policy “unconscionable”.
Why has the US decided to quit?
The decision to leave the body follows years of US criticism.
The country initially refused to join the council in 2006, arguing that, like the old commission, the UNHRC had admitted nations with questionable human rights records.
It only joined in 2009 under President Barack Obama, and won re-election to the council in 2012.
But human rights groups voiced fresh complaints about the body in 2013, after China, Russia, Saudia Arabia, Algeria and Vietnam were elected members.
This followed Israel’s unprecedented boycott of one of the council’s reviews, alleging unfair criticism from the body.
Last year, Nikki Haley told the council it was “hard to accept” that resolutions had been passed against Israel yet none had been considered for Venezuela, where dozens of protesters had been killed during political turmoil.
Israel is the only country that is subject to a permanent standing agenda item, meaning its treatment of the Palestinians is regularly scrutinised.
On Tuesday, despite her harsh words for the UNHRC, Ms Haley said she wanted “to make it crystal clear that this step is not a retreat from our human rights commitments”.