At least 10 US Air Force refuelling aircraft have departed RAF Mildenhall in Suffolk, Britain, and moved to other locations across Europe amid reported security concerns linked to Iran. Flight-tracking data reviewed by BBC Verify showed the aircraft leaving the base on Monday and landing at American military installations in Europe, as well as Prestwick Airport in Scotland.

The departures have raised questions about security at US-operated military facilities in Britain. The Wall Street Journal reported that the aircraft movements were linked to a threat from Iran. However, the BBC said it had not independently verified that claim.

RAF Mildenhall military airbase in Suffolk, England
RAF Mildenhall is a key US military facility in the United Kingdom. Image: Collected

According to publicly available Flightradar24 data, several US KC-135 refuelling tankers left RAF Mildenhall throughout Monday. Two aircraft initially travelled towards US bases in Germany and Italy. One returned to Mildenhall before flying east again and landing at Spangdahlem Air Base in Germany. Another flew circuits over Aviano Air Base in Italy before also heading to Spangdahlem. Eight additional KC-135 aircraft were later tracked leaving Mildenhall.

One aircraft that landed at Prestwick Airport in Ayrshire was identified as belonging to the Nebraska Air National Guard. Its stop may have been part of a routine journey before returning to its US base.

The British Ministry of Defence declined to comment specifically on the aircraft movements. A spokesperson said military aircraft and other assets regularly move according to operational requirements. The US Air Force also stated that aircraft rotate between installations for training and operational needs, but declined to provide further details for security reasons.

Downing Street has maintained that British military bases remain safe. The prime minister's spokesperson said protecting military facilities in the UK and overseas was a priority and that the government worked closely with police and international allies. Education Secretary Lucy Powell also stressed that the government took the security of its bases seriously.

The latest movements come weeks after US bombers were withdrawn from RAF Fairford in Gloucestershire following a suspected security incident. In September, a major incident was declared after three suspicious vans were reported near the base. Eight men were arrested during a counter-terrorism investigation into an alleged Iran-linked plot, while two British nationals appeared in court in October.

Former UK National Security Adviser Lord Ricketts described military airbases as potentially vulnerable because of their large aircraft and extensive perimeters. He suggested the aircraft movements could reflect an abundance of caution. Meanwhile, US Secretary of State Marco Rubio said Washington would move personnel away from locations when intelligence indicated a potential threat.

The reason behind the latest US Air Force tankers movements has not been officially confirmed. Both governments have avoided discussing specific operational details, while questions remain about the intelligence that may have prompted the aircraft relocations.