The Palestinians threatened on Saturday to suspend all communication with the United States if the Trump administration follows through with plans to close their diplomatic office in Washington. The potential rupture in relations threatens to undermine Donald Trump’s bid for Middle East peace – a mission he has handed his son-in-law, Jared Kushner.

Senior Palestinian negotiator Saeb Erekat said the US decision was “very unfortunate and unacceptable,” and accused Washington of bowing to pressure from Israeli PM Benjamin Netanyahu’s government “at a time when we are trying to cooperate to achieve the ultimate deal.”

In a video statement on social media, Erekat said: “We will put on hold all our communications with this American administration.”

There was no immediate reaction from the Trump administration. Netanyahu’s office said the closure was “a matter of US law”.

US officials had insisted before Erekat’s statement that the move wasn’t aimed at increasing leverage over the Palestinians, but merely the unavoidable consequence of US law.

The administration announced late Friday that the Palestinians had run afoul of a legal provision that says the Palestine Liberation Organization (PLO) cannot operate a Washington office if the Palestinians try to get the international criminal court to prosecute Israelis for crimes against Palestinians.

Secretary of state Rex Tillerson determined that the Palestinians crossed that line in September, when Palestinian president Mahmoud Abbas called on the court to investigate and prosecute Israelis, according to state department officials. They weren’t authorized to publicly discuss the situation and spoke on condition of anonymity.

It wasn’t clear when the office would close or whether the Palestinians would have to clear out of the building entirely or just close it to the public.

Under the law, Trump now has 90 days to consider whether the Palestinians are in “direct and meaningful negotiations with Israel”. If Trump determines they are, then the mission can reopen, officials said.

PLO official Hanan Ashrawi said the US was “disqualifying itself as a peace broker in the region” by refusing to extend a waiver from the law.

The US said it wasn’t cutting off relations with the Palestinians and remained focused on a comprehensive peace agreement between Israelis and Palestinians. One of the US officials said in an email that “this measure should in no way be seen as a signal that the US is backing off those efforts”.

The Israelis and Palestinians are not engaged in active, direct negotiations. But Trump’s team, led by senior White House adviser Jared Kushner, is working to broker a deal aimed at settling the intractable conflict.

The Palestinians, publicly supportive of the US effort, are nonetheless skeptical because Trump’s close ties to Israel suggest whatever deal he proposes might be unfavorable to them. The threat of losing their office in the American capital could become another pressure point as the Trump administration tries to persuade the Palestinians to come to the table.

The United States allowed the PLO to open a mission in Washington in 1994. That required President Bill Clinton to waive a law that said the Palestinians couldn’t have an office. In 2011, under the Obama administration, the US started letting the Palestinians fly their flag over the office, an upgrade to the status of their mission that the Palestinians hailed as historic.

Israel opposes any Palestinian membership in UN-related organizations until a peace deal has been reached.