US President Donald Trump is likely to announce next week that the United States recognizes Jerusalem as Israel’s capital, a senior administration official said on Friday, a move that would upend decades of American policy and possibly inflame tensions in the Middle East, Reuters reported.

Trump could make the controversial declaration in a speech on Wednesday though he is also expected to again delay his campaign promise to move the U.S. embassy to Jerusalem from Tel Aviv. The senior official and two other government sources said final decisions had not yet been made.

The Palestinians want Jerusalem as the capital of their future state, and the international community does not recognize Israel’s claim on all of the city, home to sites holy to the Jewish, Muslim and Christian religions.

Word of Trump’s planned announcement, which would deviate from previous U.S. presidents who have insisted the Jerusalem’s status must be decided in negotiations, drew criticism from the Palestinian Authority and was sure to anger the broader Arab world.

It could also unravel the U.S. administration’s fledgling diplomatic effort, led by Trump’s son-in-law and senior adviser Jared Kushner, to restart long-stalled Israeli-Palestinian peace talks and enlist the support of U.S. Arab allies.

Nabil Abu Rdainah, spokesman for Palestinian President Mahmoud Abbas, said U.S. recognition of Jerusalem as Israel’s capital would “destroy the peace process” and “destabilize the region.”