A general view shows the headquarters of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in Paris, France, Oct. 4, 2017.
A general view shows the headquarters of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in Paris, France, Oct. 4, 2017.

PARIS - The United States says it is withdrawing from UNESCO, accusing the organization of "anti-Israel" bias.

"This decision was not taken lightly, and reflects U.S. concerns with mounting arrears at UNESCO, the need for fundamental reform in the organization, and continuing anti-Israel bias at UNESCO," State Department spokesman Heather Nauert said in a statement. "The United States indicated to the Director General its desire to remain engaged with UNESCO as a non-member observer state in order to contribute."

The U.S. withdrawal will take effect on December 31 2018, the State Department confirmed.

Hours later, Israel announced that it would also be leaving the U.N. body.

"The prime minister instructed the foreign ministry to prepare Israel's withdrawal from the organisation alongside the United States," Israeli Prime Minister Benjamin Netanyahu's office said in a statement.

Netanyahu "welcomes the decision by President (Donald) Trump to withdraw from UNESCO. This is a courageous and moral decision because UNESCO has become the theatre of the absurd and because instead of preserving history it distorts it."

UNESCO, the U.N. Educational, Scientific, and Cultural Organization, responded with regret over the decision.

"I believe in all these years we have forged—and particularly these last time—we have forged a very strong partnership, very, I believe, relevant to the foreign policy agenda an overall agenda of the United States," director general Irina Bokova told a news conference. "So it is with deep regret that today I received the letter from the Secretary of State.”

Bokova went on to note that the United States would remain involved with UNESCO as an observer, and that the United States, a founding member of the agency, would be given the opportunity to come back.

The U.S. ambassador to the U.N. Nikki Haley said the decision was necessary after an "outrageous and politically based decision" to designate the Old City of Hebron and the Tomb of the Patriarchs as part of Palestinian territory.

"The purpose of UNESCO is a good one. Unfortunately, its extreme politicization has become a chronic embarrassment," she said in a statement. "U.S. taxpayers should no longer be on the hook to pay for policies that are hostile to our values and make a mockery of justice and common sense."

House Foreign Affairs Committee Chairman Ed Royce said the move was "unfortunate but appropriate given UNESCO’s mismanagement and disturbing anti-Israel bias" in a statement Thursday.

The United States cancelled a significant budget contribution to the organization in 2011 in protest of a decision to grant full membership to the Palestinians. Washington opposes any more by the U.N. to recognize a Palestinian state before a Middle East peace deal is reached.

President Ronald Reagan withdrew the U.S. from UNESCO in 1984 over alleged financial mismanagement and anti-U.S. bias in some of its policies, but joined again under President George W. Bush in 2002.

The Paris-based organization, founded in 1946, is best known for designating World Heritage sites such as the ancient city of Palmyra in Syria and the Grand Canyon National Park.

VOA's Nike Ching and Margaret Besheer contributed to this report.