A US Air Force refuelling tanker has landed at Prestwick Airport after an unspecified threat prompted the precautionary relocation of American aircraft from RAF Mildenhall in Suffolk.

The Stratotanker touched down at the South Ayrshire airport on Tuesday afternoon, a day after US tankers began moving to Germany and other locations. Reports have suggested a possible link to Iran, but the exact nature of the threat remains unknown and was reportedly still under discussion among US officials.

Two US refuelling tankers stationed at Mildenhall were reportedly diverted to Germany on Monday morning, with several more moved to Germany and elsewhere later that day. The aircraft’s arrival in Scotland forms part of that wider dispersal rather than an isolated diversion.

Downing Street has insisted that British air bases remain safe and described their security as a “top priority”. That assurance addresses the safety of the bases, but does not explain the specific threat behind the American decision to move aircraft.

The relocation comes weeks after the US withdrew its bombers from RAF Fairford in Gloucestershire following a suspected Iran-related terror incident near the airbase. The suspected Iranian connection to that earlier incident and the reported link to the latest threat remain qualifications, not established evidence of a common cause.

An RAF Voyager also landed at Prestwick shortly after the US tanker on Tuesday afternoon. No connection between its arrival and the precautionary moves has been specified.