The United States is pulling out of UNESCO because of what Washington sees as its anti-Israel bias and a need for “fundamental reform” of the U.N. cultural agency.

While the Trump administration had been preparing for a likely withdrawal for months, the announcement by the State Department on Thursday rocked UNESCO’s Paris headquarters, where a heated election to choose a new director is under way.

The outgoing UNESCO chief expressed her “profound regret” at the decision and tried to defend the reputation of the U.N. Educational, Scientific and Cultural Organization, best known for its World Heritage program to protect cultural sites and traditions.

The U.S. stopped funding UNESCO after it voted to include Palestine as a member in 2011, but the State Department has maintained a UNESCO office and sought to weigh on policy behind the scenes. The U.S. now owes about $550 million in back payments.

In a statement, the State Department said the decision will take effect Dec. 31, 2018, and that the U.S. will seek a “permanent observer” status instead. It cited U.S. belief in “the need for fundamental reform in the organization.”

Several diplomats who were to have been posted to the mission this summer were told that their positions were on hold and advised to seek other jobs. In addition, the Trump administration’s proposed budget for the next fiscal year contains no provision for the possibility that UNESCO funding restrictions might be lifted.

The lack of staffing and funding plans for UNESCO by the U.S. have been accompanied by repeated denunciations of UNESCO by senior U.S. officials, including U.S. Ambassador to the United Nations Nikki Haley.

U.S. officials said Secretary of State Rex Tillerson made the decision and that it was not discussed with other countries but was the result of an internal U.S. government deliberation.

The officials, who were not authorized to be publicly named discussing the issue, said the U.S. is notably angry over UNESCO resolutions denying Jewish connections to holy sites and references to Israel as an occupying power.

Many saw the 2011 UNESCO vote to include Palestine as evidence of long-running, ingrained anti-Israel bias within the United Nations, where Israel and its allies are far outnumbered by Arab countries and their supporters.

UNESCO’s outgoing director-general, Irina Bokova of Bulgaria, called the U.S. departure a loss for “the United Nations family” and for multilateralism. She said the U.S. and UNESCO matter to each other more than ever now to better fight “the rise of violent extremism and terrorism.”

She defended UNESCO’s reputation, noting its efforts to support Holocaust education and train teachers to fight anti-Semitism — and that that the Statue of Liberty is among the many World Heritage sites protected by the U.N. agency. UNESCO also works to improve education for girls in poor countries and in scientific fields and to defend media freedom, among other activities.

Other UNESCO members did not immediately comment on the U.S. departure.

It’s not the first time the U.S. pulled out of UNESCO: Washington did the same thing in the 1980s because it viewed the agency as mismanaged, corrupt and used to advance Soviet interests. The U.S. rejoined in 2003.

Top photo | A view of the Church of the Nativity, in the West Bank city of Bethlehem, a UNESCO’s World Heritage site since 2012. (AP/Nasser Shiyoukhi)