The U.S. Air Force has relocated aircraft from its base in eastern England due to a threat, U.S. officials told The Associated Press. The Military Air Tracking Alliance, a group of open-source analysts, observed 13 U.S. aircraft departing from RAF Mildenhall for bases in Scotland, Spain, and Germany.

The Wall Street Journal reported that the threat was related to Iran, citing individuals familiar with the matter. This relocation comes less than two months after the U.S. Air Force withdrew bombers from RAF Fairford, another U.S.-run base in Britain, amid a police investigation into a suspected terror plot linked to Iran. Bombers operating out of RAF Fairford had previously been used in strikes against Iran.

Aircraft that departed RAF Mildenhall included permanently based planes and others on rotation, such as Osprey aircraft and midair refueling tankers, according to the Military Air Tracking Alliance. The base also raised its alert level to FPCON Charlie, the second-highest level, indicating that a terrorist action targeting personnel or facilities is likely based on received intelligence or an incident.

A U.S. official described the aircraft movement as proactive, emphasizing the U.S. military's agility in responding to potential threats. The official stated that some planes were in transit and others were permanently stationed, with the possibility of their return, but did not specify the nature or source of the threat.

U.S. Secretary of State Marco Rubio commented that the U.S. "constantly repositioning forces around the world for a variety of reasons" and deferred questions to the Pentagon, which did not immediately confirm the details. An official from U.S. Air Force in Europe confirmed that "coordinated and appropriate actions" are being taken to ensure the safety of U.S. and U.K. personnel, noting that aircraft rotations occur for training and operational reasons. This official also stated that the U.S. military continuously assesses factors determining security measures but declined to provide further details for operational security reasons. Both officials spoke on condition of anonymity.

The U.K. prime minister's office affirmed that British air bases are secure and that the U.K. collaborates closely with the U.S. on intelligence sharing and threat assessment. RAF Mildenhall hosts the 100th Air Refueling Wing, operating KC-135 Stratotankers, and is the only permanent refueling wing in the European region.

Earlier this year, five men were detained near RAF Fairford following the sighting of suspicious vans. Subsequently, two men were charged under the National Security Act. The U.K. Defense Ministry stated that it does not comment on the activities of other nations, noting that aircraft and assets frequently move according to operational needs.