Adding to the international diplomatic pressures, the Trump administration intensified its focus on Sir Keir Starmer following the imposition of sanctions on a British activist. This individual, as reported by U.S. intelligence, has been accused of acting on behalf of Hamas.

In a move underscoring their stance, the U.S. Treasury Department’s Office of Foreign Assets Control (OFAC) declared on January 21 that it was targeting the clandestine connections between Hamas and various nonprofit organizations.

The announcement specifically identified six groups based in Gaza, along with the Popular Conference for Palestinians Abroad (PCPA), as being linked to Hamas. U.S. authorities accused the PCPA of serving as a façade for Hamas’s activities on the global stage.

Among those designated was Zaher Birawi, 64, whom OFAC accused of holding a significant leadership position within Hamas through his involvement with the PCPA. His designation by OFAC underscores the U.S. efforts to dismantle what they describe as Hamas’s covert networks.

The Trump administration sanctioned Britain-based activist Zaher Birawi, who is accused of Hamas ties, pressuring Prime Minister Sir Keir Starmer to take similar action against the London resident. (Mark Kerrison/In Pictures via Getty Images)

The Treasury Department said Birawi is a founding member of the organization and part of its general secretariat, alleging the group was used to “clandestinely expand” Hamas’ international influence and fundraising.

This included backing flotillas that attempted to reach Gaza. Some have received public backing from prominent activists, including Greta Thunberg.

“Hamas continues to show a callous disregard for the welfare of the Palestinian people,” John K. Hurley, the U.S. Undersecretary for Terrorism and Financial Intelligence, said in a statement.

Hurley added that “the Trump administration will not look the other way while Hamas leadership and enablers exploit the financial system to fund terrorist operations.”

Greta Thunberg with Zaher Birawi (second from the left), who Israel says is linked to Hamas. (Israel’s Ministry of Foreign Affairs)

The sanctions have put pressure on the U.K., which has been reviewing possible counterterror measures against Birawi for weeks, according to The Times.

U.K. Shadow Home Secretary Chris Philp said it was “good to see” the U.S. take action, adding, “Under no circumstances should Britain be a place of sanctuary for anyone involved in or supportive of terrorist (organizations) like Hamas.”

Alex Hearn of Labour Against Antisemitism said Birawi continued to broadcast from London and organize flotillas despite the U.S. designation.

Lord Austin of Dudley has urged the U.K. to examine the intelligence “very carefully.”

British Prime Minister Keir Starmer, left, and U.S. President Donald Trump shake hands at a joint press conference in the East Room at the White House Feb. 27, 2025, in Washington. (Carl Court/Pool Photo via AP)

Birawi, who lives in Barnet in north London, has been in the U.K. for more than 30 years.

He chairs the Palestine Forum in Britain and is a prominent organizer of pro-Palestinian demonstrations in the city.

He has been named in Parliament as a security concern, and Israel designated him a Hamas member in 2013, allegations he has consistently denied.

In 2023, Birawi said he is a “law-abiding British citizen” and rejected claims of links to Hamas, saying his work focuses on “defending the national and human rights of Palestinians who survive under occupation.”

Fox News Digital has reached out to Birawi and Sir Keir Starmer’s office for comment.