President Trump said today that the United States should recognize Israel’s authority over the Golan Heights, one of the world’s most disputed territories, reversing decades-long American policy and violating a United Nations resolution.

Trump’s announcement, in a midday Twitter post, serves to recognize Israeli sovereignty over land that its troops seized in war.

It came after repeated pressure from Prime Minister Benjamin Netanyahu of Israel, which claimed the Golan Heights from Syria in 1967 and effectively annexed it in 1981.

The United Nations Security Council has declared that Israel must withdraw from territory acquired by force.

In an interview today with the Fox Business Network, Trump said that he had considered recognizing the territory as part of Israel “for a long time” and that his decision was not meant to boost Netanyahu’s chances in a bitter race for coming parliamentary elections.

“I wouldn’t even know about that,” Trump said of the Israeli vote, set for April 9. “I’m the one that gets it done.”

After 52 years it is time for the United States to fully recognize Israel’s Sovereignty over the Golan Heights, which is of critical strategic and security importance to the State of Israel and Regional Stability! — Donald J. Trump (@realDonaldTrump) March 21, 2019

The White House refused to comment or offer clarification on whether Trump’s tweet amounted to actual policy change on the Golan Heights, an area of land in Syria that abuts the borders of Israel, Jordan and Lebanon.

But Netanyahu tweeted a note of thanks to Trump within minutes of the president’s announcement.

At a time when Iran seeks to use Syria as a platform to destroy Israel, President Trump boldly recognizes Israeli sovereignty over the Golan Heights. Thank you President Trump! @realDonaldTrump — Benjamin Netanyahu (@netanyahu) March 21, 2019

Trump’s announcement is at odds with international law and decades of American policy in the Middle East.

The United Nations and the United States have steadfastly refused to recognize Israel’s seizure of the Golan Heights and the West Bank in the Arab-Israeli War of 1967, arguing that the contours of Israel and a new Palestinian state must be negotiated diplomatically.

Since then, Israel has treated the territory as part of its country, and the Jewish population has grown with the expansion of Israeli settlements.

Syria has often criticized Israel’s settlement of the territory in international forums.

The shift from Washington also has profound consequences for the Israeli-Palestinian peace plan being drafted by Trump’s son-in-law and senior adviser, Jared Kushner, since it will confront Arab leaders with the choice of acquiescing in Israel’s annexation of Arab land.

“What shall tomorrow bring?” Saeb Erekat, the secretary-general of the Palestine Liberation Organization and a veteran Palestinian negotiator, said in a tweet. “Certain destabilisation and bloodshed in our region.”

Analysts expressed outrage at Trump’s statement, saying that it violated the United Nations resolution adopted after the 1967 war and would embolden other leaders who seized territory.

“Putin will use this as a pretext to justify Russia’s annexation of Crimea,” said Martin S. Indyk, a former peace negotiator and American ambassador to Israel. “The Israeli right will use it as a pretext for Israel’s annexation of the West Bank. It is a truly gratuitous move by Trump.”