WASHINGTON (Reuters) - The United States revoked visas for the family of the Palestine Liberation Organization ambassador, the envoy said on Sunday, the latest development in the worsening relations between the Trump administration and Palestinian leadership.

A tattered flag flies over the Palestine Liberation Organization (PLO) office two days after President Donald Trump's national security adviser John Bolton announced that the State Department would close the PLO office in Washington, U.S., September 12, 2018. REUTERS/Kevin Lamarque

Ambassador Husam Zomlot, head of the PLO General Delegation to the United States, said his family, including his two young children, left the United States after being informed their visas would now expire when the diplomatic office is closed next month. The visas were originally set to expire in 2020.

The Trump administration said last Monday the office in Washington would close. The State Department did not respond to a request for comment.

Hanan Ashrawi, a member of the PLO’s executive committee, criticized the Trump administration for being “vindictive.”

“As if the announcement that the US would close our office in Washington, DC was not enough, this vindictive action by the Trump administration is spiteful,” Ashrawi said in a statement. “The US has taken its attempts to pressure and blackmail the Palestinians to a new level.”

Zomlot said in an interview that two of his embassy employees met last week with State Department staff, who had requested the meeting.

“The State Department informed our colleagues, as part of the discussion on the closure, that the visas of my wife and children are dependent on the PLO delegation and as such will not be valid after the closure of the office and that if they wanted to stay they would have to change their immigration status,” Zomlot said.

He added: “This goes against diplomatic norms. Children, spouses and family have nothing to do with political rows.”

Last month, the United States halted all funding to a U.N. agency that helps Palestinian refugees.

The Palestinian leadership has angered the White House by boycotting its peace efforts since President Donald Trump recognized Jerusalem as Israel’s capital and moved the embassy there, reversing decades of U.S. policy.

The status of Jerusalem - home to sites holy to the Muslim, Jewish and Christian religions - is one of the biggest obstacles to any peace agreement between Israel and the Palestinians.

Palestinians claim East Jerusalem for the capital of an independent state they seek. Israel says Jerusalem is its eternal and indivisible capital.

Trump’s son-in-law and senior adviser, Jared Kushner, is leading an effort to craft a peace plan meant to launch negotiations between Israel and the Palestinians to end a decades-long conflict. A decision on when the initiative would be rolled out has not yet been made.