The United States has moved military aircraft out of RAF Mildenhall in Suffolk after a threat linked to Iran, the Wall Street Journal reported on Monday, in the second such move from a British base in a matter of weeks.

Two US refuelling tankers were diverted to Germany on Monday morning, and several more were moved to Germany and other locations later in the day, the newspaper said, citing people familiar with the matter and flight-tracking data.

The exact nature of the threat to the Suffolk base remains under discussion among US officials, who have not said whether it was imminent or more general.

Security raised at two Suffolk bases

The US military also raised the security posture at RAF Mildenhall and nearby RAF Lakenheath to Force Protection Condition Charlie, the second-highest level in the Pentagon's force protection system. The level is used when intelligence indicates that a form of terrorist action is likely, and it sits one step below the highest alert, Delta.

The change was first reported by the defence publication The War Zone, which cited a US official, and was later confirmed by the Wall Street Journal.

A US Air Force spokesperson declined to give details of the aircraft movements, saying only that American aircraft rotate between installations and operating locations for a variety of reasons, including training and real-world requirements.

A UK Ministry of Defence spokesperson said Britain does not routinely comment on the activity of other nations, adding that aircraft and other assets move regularly according to operational requirements.

Second base in weeks

Mildenhall is the second British base from which the US has pulled aircraft over an Iran-linked threat. Last month, B-1 bombers were flown back to the United States from RAF Fairford in Gloucestershire after five men were arrested outside the base in the early hours of 27 September.

British prosecutors later charged two British nationals under the National Security Act in connection with that incident, with police saying the two were suspected of assisting Iran.

RAF Mildenhall is home to the US Air Force's 100th Air Refueling Wing, which operates KC-135 Stratotanker aircraft, as well as reconnaissance and special operations units. RAF Lakenheath hosts US fighter squadrons.

Wider tensions

The moves come against the backdrop of the war between the United States and Israel and Iran, which began in February, and continued tension over the Strait of Hormuz, which Iran has kept effectively closed to commercial traffic.

President Donald Trump said on Monday that he believed the war with Iran was militarily effectively over and that fresh strikes were not necessary for now, while warning that the US remained "locked and loaded".

But US officials have continued to warn of Iranian threats to American personnel. The director of national intelligence, Jay Clayton, said in October that Iran was in the "advanced stages" of planning to target US personnel in the Middle East.

US officials have not said when the aircraft moved from Mildenhall will return to the base.