Five men were arrested early Sunday near RAF Fairford, a British air base run by the U.S. military, first on suspicion of explosives offences and then on suspicion of preparing a terrorist act. Police declared a major incident and advised about 85 households in a nearby village to leave their homes.
According to Counter Terrorism Policing, the UK's national police network for terrorism cases, officers took a call at about 12:45 a.m. Sunday about three suspicious vehicles that appeared to be heading toward the base in Gloucestershire, in western England.
Armed officers responded and arrested five men in the Whelford area. They were first held under the Explosives Act. They were then further arrested under section 5 of the Terrorism Act, the provision that covers preparing acts of terrorism.
"We are in the early stages of an investigation, and five men remain in custody," Deputy Assistant Commissioner Vicki Evans, Counter Terrorism Policing's Senior National Coordinator, said, as reported by PBS News.
Police have not released the men's names or nationalities, and have not described a motive. No charges have been reported. British police also have not confirmed that RAF Fairford was the intended target, TIME reported.
Why a major incident was declared
Gloucestershire Police's first statement tied the major incident to the arrests on suspected explosives offences. It said properties in Whelford were being evacuated after the declaration, that the Army's specialist bomb disposal team was examining a number of vehicles, and that residents were being taken to a nearby leisure centre.
"A cordon is currently in place but we’d like to reassure people that we believe this incident is contained," the force said in that statement, according to Euronews. The force added that it was working closely with partners and following well-rehearsed plans. Officials have not spelled out any other criteria behind the declaration.
By Sunday afternoon, Assistant Chief Constable Richard Ocone of Gloucestershire Police told reporters that a 400-meter cordon surrounded the vehicles while the Army's Explosive Ordnance Disposal unit examined them.
Ocone said about 85 households had been advised to leave as a precaution while those checks continue. The leisure centre was opened for people unable to stay with friends or family. Police have not said when residents can go home or when the cordon will be lifted.
Police have not described what, if anything, was found in the vehicles. Earlier in the day, CBS News reported that police had not confirmed which vehicles were being examined or whether they were connected to the incident.
Why counter-terrorism officers took over
Counter Terrorism Policing took the case from the local force because the Metropolitan Police has lead responsibility for suspected terrorism nationwide, PBS News reported.
The terrorism arrests also lengthen how long the men can be held. The Terrorism Act 2000 allows detention without charge for up to 14 days, against 24 hours for a standard arrest.
What the base does
RAF Fairford sits about 100 miles west of London. Britain owns it, but the U.S. operates it under an agreement that PBS News dates to the Cold War and CBS News to the 1950s. CBS said it is one of several British bases the U.S. Air Force uses.
The U.S. Air Force says the base houses the headquarters of the 501st Combat Support Wing and the 420th Air Base Squadron, Euronews reported. The Air Force also calls it the favored site in Europe for forward bomber operations by its Global Strike Command.
That role has taken on new weight since the U.S. and Israel launched their war on Iran on Feb. 28. Britain limited U.S. operations from Fairford to defensive missions, such as strikes on Iranian missile sites, under terms agreed with then-Prime Minister Keir Starmer, PBS News reported. Starmer voiced opposition to the war after it began.
In July, Iran's Revolutionary Guards warned Britain against letting U.S. bombers fly from Fairford, naming B-1 aircraft based there. "Any base that is used to invade Iran's territory is our legitimate goal," the Guards said in a statement shared by the semi-official Tasnim news agency, Euronews reported.
British worry about hostile states was already high. In March, officials reported a 50% jump in national security cases tied to hostile states, Iran among them, over the six months ending in December 2025, according to PBS News. Security officials in Britain have also blamed Iran-linked proxies for a series of attempted arson and sabotage attacks at home and abroad, frequently directed at Jewish communities.
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The Associated Press reported that authorities are examining a possible link to Iran as one line of inquiry. TIME noted that no such link has been confirmed.
What officials say about the risk
Police have said they believe the incident is contained and that the evacuations are precautionary.
A U.S. Air Force spokesperson said American and British personnel at the base remain vigilant, but declined to discuss force protection measures. "We constantly assess a variety of factors that determine what measures we institute or modify to protect our installations, our people and their families," the spokesperson said, according to PBS News.
U.S. European Command also declined to detail specific steps, CBS reported, while pledging to protect U.S. troops, civilian staff, contractors and their families across Europe.
U.S. Defense Secretary Pete Hegseth and British Defence Secretary Wes Streeting have spoken about the incident, though what they discussed has not been disclosed. Streeting thanked emergency and specialist teams and said people could be reassured the incident was being handled.
Reactions from London and Washington
Prime Minister Andy Burnham, who took office in July, said the incident would be deeply concerning, thanked police, the armed forces and evacuated residents, and said public safety was the top priority.
"The investigation remains ongoing, and I would urge people not to speculate while the authorities establish the full facts," Burnham wrote on X, TIME reported.
President Donald Trump, speaking to reporters in Chicago, praised the arrests as fantastic. "We had them under view for a long time and we got them," he said, according to PBS News. He also said, "They were looking to do big damage to our fort."
British police have not said the men were under surveillance. ITV News, citing the PA news agency, reported that the operation was not intelligence-led, meaning investigators had not known about a potential plot in advance.
All five men remain in custody while the Army's examinations continue. Under terrorism law, police can hold them for up to 14 days before they must be charged or released.