The US has withdrawn all of its bombers from RAF Fairford, the UK military base at the centre of an incident being investigated by counter terror police.

A statement from a Pentagon official 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.

The US did not give a reason for the withdrawal, but it follows a major incident on 27 September when police were alerted to three “suspicious vehicles” near the airbase.

Five men were initially arrested on suspicion of terror offences near the base and subsequently released on bail. A sixth man, a UK-Iranian national, was also later arrested and released on bail.

Whitehall sources have not disputed the decision from Washington was in response to the incident at the airbase in Gloucestershire.

The BBC has also been told it was a military rather than a political decision – taken at an operational level – and communicated from the US military to its British counterparts.

The UK’s Ministry of Defence has not commented.

Tracking websites showed B-1 bombers flying out of RAF Fairford on Sunday.

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. Tehran has strongly denied any involvement.