US President Donald Trump has said the United States moved its bombers out of RAF Fairford because of "some threats" to the base.
The Pentagon confirmed on Sunday it had removed its bombers - thought to be about a dozen B-1s - from the base back to their home stations in America.
Speaking to reporters as he departed for Nebraska on Monday, Trump said the US knew of a "threat", which led them to move the bombers.
Earlier on Monday, a No 10 spokesperson had insisted RAF Fairford was safe and pointed to Trump's comments last week, where he praised "our police, defence and security services" in relation to the base.
Trump's comments appear to confirm reports by US media that a new threat had led to the bombers being removed, which follows a major incident on 27 September when police were alerted to three "suspicious vehicles" near the airbase.
While speaking to a gaggle of reporters outside the White House in Washington, Trump was asked if there was a "specific threat" that led the US to pull it's bombers from the airbase.
Trump replied: "Yeah I think we can say that. They didn't fly out by accident.
"There were some threats. And rather than tempting the enemy, we'll capture the enemy and beat the enemy. But why should we leave them there? So we moved them around a little bit. Not very far."
He added that Washington "actually knows the people that made the threat", but did not confirm who.
RAF Fairford - in the Cotswolds in Gloucestershire - has been at the centre of an incident being investigated by counter-terror police.
Five men were initially arrested on suspicion of terror offences and subsequently released on bail. A sixth man, a UK-Iranian national, was also later arrested and released on bail.
Following the release of the first five men, Trump criticised the decision and US officials suggested Iran could have been involved in the incident.
Whitehall sources have not disputed that the decision from Washington to remove the bombers was in response to the incident at the airbase in Gloucestershire.
Speaking earlier on Monday, US Secretary of State Marco Rubio said he would not directly tie last week's incident to the decision to pull bombers from RAF Fairford.
He added: "It's not unusual to see movement of assets to different parts of the world based on exercises, redeployments, people changing out and new people coming in, new planes coming in and old planes going out."
Rubio said the US still has full confidence in the security of all its bases and that British authorities have been very cooperative since the incident.
US Vice President JD Vance later said the bombers were moved out of an "abundance of caution", adding Washington feels Iran is doing what it has "done for 49 years... which is engage in acts of terrorism against the US and against a lot of other people".
Days after the incident at RAF Fairford, Prime Minister Andy Burnham said there were "strong indications" that Iran had played a part in the incident but did not provide further details, while US Secretary of State Marco Rubio said on Fox News that it "clearly involve[d] the hands of a foreign actor" without going into further details.
Tehran has strongly denied any involvement.
In July, Iran said "any base used for aggression against Iranian territory constitutes a legitimate target for our forces".
RAF Fairford, near the Cotswolds village of Whelford, has been used as a forward operating location by the USAF for decades.
In recent months, the US has flown B-1 and B-52 bombers from the base for the Middle East, after the UK approved a US request to use it for defensive strikes on Iran.