The US military evacuated aircraft from a second air base in Britain on Monday after a threat from Iran, the Wall Street Journal reported, citing people familiar with the matter, weeks after a suspected Iran-linked security incident at the RAF Fairford ‌air base led ‌to the withdrawal of ‌US bombers.

Two US refueling tankers that were using the RAF Mildenhall military base diverted to Germany earlier in the morning, while several other tankers at the base were moved to Germany and other locations later in the ‌day, the ‌WSJ report said. According to the Journal, the ‌precise nature of the threat to ‌RAF Mildenhall remains under discussion among US officials. “We do not routinely comment on the activity of other nations. ‌Aircraft and other assets move regularly according to operational requirements,” a British ministry of defense spokesperson said.

Five British men were arrested outside the RAF Fairford base in southwest England in September, prompting the US to remove its B-1 bombers from that air base shortly after on security grounds.

RAF Fairford had been used by US bombers to carry out strikes on Iran.