Washington blames UK base incident on a 'foreign actor'

US Secretary of State Marco Rubio said the "hands of a foreign actor" were involved in an incident in which five men were arrested on suspected explosives and terrorism offenses near a British air base used by US forces.

Police detained the five men, all British nationals from London, early on Sunday after reports of three suspicious vans in the Gloucestershire village of Whelford, which is adjacent to the UK-owned air base that is operated by the United States.

Counterterrorism police rapidly locked down the area, evacuated around 85 households for 36 hours, and deployed bomb disposal robots to examine the vehicles.

But by Monday, all five men, arrested on suspicion of offenses under the Explosives Act, had been released on bail with strict conditions.

Rubio, speaking to US media, declined to elaborate but thanked British authorities for being "cooperative" and "helpful".

"I have to be careful, there are some things I cannot say on the air for a lot of different reasons. Suffice it to say that what happened, what almost happened, what could have happened, in the UK over the weekend is a very serious situation. It's one that clearly involves the hands of a foreign actor.

"I know a lot of people are disturbed by the news that some of these people have been released on bail, some of the people are being investigated. Obviously we're engaging with them on all of that."

US President Donald Trump expressed surprise at the suspects' release. "We know everything about them. We would not have released them," he said.

The UK base has recently been used by US warplanes as a staging post for "defensive" strikes on Iran.

Asked whether Iran was involved, Trump said, "It might be", but declined to elaborate. "I'd rather not. I mean, I know the answer, I could be very specific, but I'd rather not say. I would not have released them."

Iran's Revolutionary Guard Corps declared the base a legitimate target in July, though Tehran's embassy in London has denied any involvement in the incident, news agencies reported. Trump suggested US authorities knew about the plot, even as British sources said they remained uncertain what the men had been doing. Police said they initially believed the vans contained explosives and assessed whether they might be viable improvised devices. No explosive material was ultimately found.