The United States has withdrawn all of its bombers from RAF Fairford in Gloucestershire, the British military base at the centre of a counter-terrorism investigation.
A US Department of Defense official confirmed that the bombers had been moved from the base back to their home stations in the United States.
Washington has not given a reason for the withdrawal. However, it follows a major security incident on 27 September, when police were alerted to three "suspicious vehicles" near the airbase.
Five men were initially arrested on suspicion of terrorism offences and were later released on police bail. A sixth man, a UK-Iranian national, was subsequently arrested and also released on bail.
Whitehall sources have not disputed reports that the US decision was connected to the incident at RAF Fairford.
The withdrawal is understood to have been a military and operational decision, rather than a political one, and was communicated by the US military to its British counterparts.
The UK's Ministry of Defence has not commented on the move.
Days after the incident, Prime Minister Andy Burnham said there were "strong indications" that Iran had played a role, although he did not provide further details.
Iran has strongly denied any involvement in the incident.
The investigation remains ongoing.
