Washington (CNN) US Ambassador to the United Nations Nikki Haley announced the United States is withdrawing from the UN Human Rights Council Tuesday, accusing the body of bias against US ally Israel and a failure to hold human rights abusers accountable.

The move, which the Trump administration has threatened for months, came down one day after the Office of the UN High Commissioner for Human Rights slammed the separation of children from their parents at the US-Mexico border as "unconscionable."

Speaking from the State Department, where she was joined by Secretary of State Mike Pompeo, Haley defended the move to withdraw from the council, saying US calls for reform were not heeded.

"Human rights abusers continue to serve on, and be elected to, the council," said Haley, listing US grievances with the body. "The world's most inhumane regimes continue to escape its scrutiny, and the council continues politicizing scapegoating of countries with positive human rights records in an attempt to distract from the abusers in its ranks."

'Deeply disappointed'

"For too long," Haley said, "the Human Rights Council has been a protector of human rights abusers, and a cesspool of political bias."

Based in Geneva, the Human Rights Council is a body of 47 member states within the United Nations tasked with upholding human rights.

Membership on the council gives countries like the United States a voice in important debates over human rights atrocities, but the council's critics, including Haley, say abusers use their membership to guarantee their own impunity.

Vice President Mike Pence tweeted a statement: "Today the US took a stand against some of the world's worst human rights violators by withdrawing from the United Nations Human Rights Council. By elevating and protecting human rights violators and engaging in smear campaigns against democratic nations, the UNHRC makes a mockery of itself, its members, and the mission it was founded on. For years, the UNHRC has engaged in ever more virulent anti-American, and anti-Israel invective and the days of U.S. participation are over."

The UN expressed disappointment. "The Secretary-General would have much preferred for the United States to remain in the Human Rights Council," Stéphane Dujarric, the spokesman for UN Secretary-General António Guterres, said in response to the US announcement. "The UN's Human Rights architecture plays a very important role in the promotion and protection of human rights worldwide."

The move was immediately condemned by a dozen charitable groups, who wrote to Pompeo to say they were "deeply disappointed with the Administration's decision to withdraw the United States from the United Nations Human Rights Council, the premier intergovernmental human rights body at the global level."

Israeli Prime Minister Benjamin Netanyahu praised the move however, thanking Trump and Haley for their "courageous decision against the hypocrisy and the lies of the so-called UN Human Rights Council."

"For years, the UNHRC has proven to be a biased, hostile, anti-Israel organization that has betrayed its mission of protecting human rights," he said.

'A so-called Human Rights Council'

"This decision is counterproductive to American national security and foreign policy interests and will make it more difficult to advance human rights priorities and aid victims of abuse around the world," they added.

Salil Shetty, Amnesty International's secretary-general, said: "Once again President Trump is showing his complete disregard for the fundamental rights and freedoms the US claims to uphold. While the Human Rights Council is by no means perfect and its membership is frequently under scrutiny, it remains an important force for accountability and justice."

US withdrawal from the council follows efforts by Haley and the US delegation to implement reforms, including more stringent membership criteria and the ability to remove members with egregious human rights records.

"When a so-called Human Rights Council cannot bring itself to address the massive abuses in Venezuela and Iran, and it welcomes the Democratic Republic of Congo as a new member, the council ceases to be worthy of its name," said Haley. "Such a council, in fact, damages the cause of human rights."

Haley also blasted the council for a "disproportionate focus and unending hostility toward Israel," citing a series of resolutions highlighting alleged abuses by the Israeli government of Palestinians in Gaza and the West Bank.

Haley said the United States will continue to promote human rights outside of the council and would consider rejoining it in the future if reforms are made.

"We have used America's voice and vote to defend human rights at the UN every day," she said, "and we will continue to do so."