US bombers used a British airbase to attack Iran overnight on Tuesday after the UK prime minister approved the use of UK bases for "defensive" military action against Iran.
Three B-1 Lancers were pictured returning to RAF Fairford on Wednesday morning after a suspected bombing operation in Iran.
They were deployed on Tuesday, a day that US Secretary of War Pete Hegseth said would see the "most intense" attacks of the 11-day war so far.
The US military has deployed a fleet of heavy bombers at the Gloucestershire airbase in recent days as it intensifies its bombing campaign in Iran.
Three B-52 bombers were pictured arriving on Monday, a few days after four B-1s landed at the Cotswold base.
B-52s are the largest bombers in the US Air Force and can carry more than 31 tonnes of ordnance over a distance of more than 14,000 kilometres.
Their return followed another heavy night of US-Israeli bombing in Tehran. Journalists in the city reported a series of explosions in the north and west of the capital. The targets were not immediately clear.
RAF Fairford is one of several airbases on the British mainland used by the US military. RAF Lakenheath in Suffolk is home to F-35 and F-15 squadrons, while RAF Mildenhall hosts a fleet of refueling aircraft.
The British base on the Pacific island of Diego Garcia is also reportedly being used for attacks against Iran.
Prime Minister Keir Starmer had initially turned down Trump's request to use British airbases to attack Iran, triggering a public spat between the two leaders.
The prime minister then U-turned on his decision on Sunday, announcing that the US Air Force would be able to use UK bases for the "specific and limited defensive purpose" of destroying Iran's missiles.
The British government has refused to join the US and Israel's war on Iran but has engaged in defensive operations, including working with Gulf states to shoot down Iranian missiles and drones.
Starmer last week said a warship would be dispatched to the Mediterranean in response to the recent drone attack on an RAF base in Cyprus.