The Palestinians threatened on Saturday to cease communication with the United States if the White House closes its diplomatic mission in Washington, D.C., lodging a potential thorn in President Trump’s plans for Mideast peace.

The State Department says the office of the Palestine Liberation Organization must close under a little-known provision in U.S. law that forbids it from requesting Israelis be prosecuted for crimes against Palestinians. Trump may reverse the closure within 90 days if the Palestinians prove they are engaging in peace negotiations with the Israelis.