UK says there are strong indications Iran played a part in a security incident at a US-run air base

LONDON (AP) — The U.K. has “strong indications” that Iran played a part in the incident that saw five men arrested near a U.S.-run military air base in England late at night, Prime Minister Andy Burnham said Wednesday.

Burnham said U.K. and U.S. officials are carrying out a “complex and serious” investigation into how and why five men and three vans were near the perimeter of RAF Fairford, a base that has been used by American bombers striking Iran during this year’s war.

Five British men in their 20s were arrested Sunday on suspicion of explosives offenses and planning an act of terror, before being released on bail a day later. Police say they found a quantity of an accelerant – gasoline – in the vans, but no explosives.

Burnham did not provide details about what the suspects were planning or why the U.K. thinks Iran was involved. He said he would “update people more in due course.”

“There are strong indications that Iran played a part in what happened over the weekend at RAF Fairford, but of course it remains an ongoing, complex, and serious police investigation,” Burnham told the BBC in one of a series of interviews with British broadcasters. “And of course, we are working closely with our colleagues in the United States of America.”

Iran has denied involvement in the incident. It has previously said that it considers any base used to attack its territory a legitimate target.

The base 100 miles (160 kilometers) west of London has been used by American bombers during decades of conflicts in the Middle East, including this year’s war with Iran.

Top U.S. officials have criticized the decision to grant the suspects bail, with President Donald Trump saying “I wouldn’t have done that” and Secretary of State Marco Rubio saying a lot of people were “disturbed” by the move.

Burnham said authorities have the investigation under “the strongest grip and the closest control,” and British officials had been “talking to counterparts in the United States all week to explain what is happening here, how things are being done.”

“I have complete confidence in the way British security services are handling this,” he told the BBC.

Laurence Taylor, the head of British counterterror policing, said Tuesday that the suspects remain under investigation and the decision to grant bail was grounded in “experience and strategy.”

He said a line of inquiry is whether the suspected offenses were committed by “proxies or individuals, either knowingly or unknowingly, working on behalf of a foreign state.”

The arrests came at a time of heightened tensions around the threat from hostile states, with British security services saying Russia and Iran have both used proxies to commit crimes on U.K. soil. British officials have said the number of national security cases involving activity by hostile states, including Iran, increased by 50% in the six months to December 2025.

U.K. officials also say proxies linked to Iran have been behind a string of arsons and other attacks in the U.K. and other countries, many of them targeting the Jewish community and intended to sow fear. They have previously warned that Tehran could expand its targets in the U.K. if conflicts in the Middle East continue.