The Trump administration has intensified pressure on Sir Keir Starmer following its designation of a Britain-based activist accused by U.S. intelligence of working for Hamas, according to reports.

The U.S. Treasury Department’s Office of Foreign Assets Control (OFAC) announced on Jan. 21 that it was “taking action against Hamas’s covert links to nonprofit organizations.”

The statement proceeded to name six Gaza-based groups and the Popular Conference for Palestinians Abroad (PCPA).

U.S. officials stated the PCPA operates as a Hamas front overseas. OFAC also designated Zaher Birawi, 64, accusing him of being a “senior official” in Hamas through his leadership role in the PCPA.

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’s international influence and fundraising.

This included supporting 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,” said John K. Hurley, the U.S. Undersecretary for Terrorism and Financial Intelligence.

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.”

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

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 stated that 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.”

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 identified 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 “” and rejected claims of links to Hamas, saying his work focuses on “defending the national and human rights of Palestinians who survive under occupation.”

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