This video can not be played

The Pentagon has confirmed that it removed its bombers - thought to be about a dozen B-1s - from RAF Fairford back to their home stations in America.

US media reported a new threat 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.

A No 10 spokesperson said he would not comment on "foreign nations' military operations", but said the base was safe.

The BBC's security correspondent Frank Gardner explains what we know about the US's decision to withdraw its bombers from the base.

More about this story.

Watch: What caused the US to remove its bombers in such a hurry? Video, 00:00:58Watch: What caused the US to remove its bombers in such a hurry?

Up Next. Watch: Detail about new call to police changes RAF Fairford timeline. Video, 00:01:17Watch: Detail about new call to police changes RAF Fairford timeline

What we know about Andrew Mountbatten-Windsor's legal action against police. Video, 00:01:20What we know about Andrew Mountbatten-Windsor's legal action against police

Watch: How Spain's housing crisis has resulted in an early general election. Video, 00:01:07Watch: How Spain's housing crisis has resulted in an early general election

How Brazil's dramatic election unfolded. Video, 00:01:27How Brazil's dramatic election unfolded

What we know about Russian strikes on Kyiv bridges. Video, 00:01:17What we know about Russian strikes on Kyiv bridges

Two people killed as floods hit Spain's Catalonia region. Video, 00:00:43Two people killed as floods hit Spain's Catalonia region

Rare tornado whips through small Australian town. Video, 00:00:31Rare tornado whips through small Australian town

Why has Brazil accused the US of election interference? Video, 00:01:57Why has Brazil accused the US of election interference?

Will Spain's housing crisis lead to a snap election? Video, 00:01:02Will Spain's housing crisis lead to a snap election?

Newly released video shows Luigi Mangione’s arrest. Video, 00:01:44Newly released video shows Luigi Mangione’s arrest

How widely used is the death penalty in the US? Video, 00:01:02How widely used is the death penalty in the US?

Watch: Emotional pilot recounts moment of Flydubai attack. Video, 00:01:05Watch: Emotional pilot recounts moment of Flydubai attack