The US has also raised the security level at RAF Mildenhall and nearby RAF Lakenheath. It's now FPCON Charlie. That's the second-highest alert level the US military has. It means intelligence suggests a terror attack is likely.
A US Air Force official wouldn't talk about the specific movements. The Air Force says quote "Aircraft often rotate between bases and operating locations for multiple reasons". The UK Ministry of Defence says it doesn't routinely comment on what other nations do.
That's everything we know.
Why this mattersSo here's the big thing. This is the second UK air base in weeks the US has pulled aircraft from over fears linked to Iran.
First it was RAF Fairford, in Gloucestershire. Early last month, the US pulled its B-1 bombers out of there. Why? Because of a suspected Iran-backed plot to target American pilots and planes on that base.
Five men were arrested outside Fairford last month. Two of them have since been charged. Their names are Mohmed Abdulkarim and Nouman Essghir. Both are 24 and from London. Prosecutors say they assisted a foreign intelligence service, and that service is Iran's.
A separate man was also arrested around the same time, in Westminster. He's 25, a British-Iranian dual national. He was arrested on suspicion of preparing terrorist acts, then rearrested alongside another man on suspicion of assisting Iran's intelligence service.
None of these men has been convicted of anything. These are allegations. Nothing has been proven in court.
Andy Burnham, the Prime Minister, has said Iran played a part in the Fairford plot. He later went further, saying it was almost certainly directed by Iran's Islamic Revolutionary Guard. Iran's embassy in London denies any of it.
And here's the thing. Iran has made this threat specific before. Back in July, the Islamic Revolutionary Guard Corps said RAF Fairford, and any other British base used to launch attacks on Iran, were fair targets.
So Mildenhall fits a pattern. A US base on British soil. American forces pulling aircraft out twice in five weeks.
Marco Rubio, the US Secretary of State, says the US is dealing with the threat by moving people out of what he calls the circle of threat. Top US congressional leaders, the Gang of Eight, got a classified briefing on Iranian threats a day ago.
But here's what nobody will say. The exact nature of the threat to Mildenhall hasn't been confirmed. US officials say it's still under discussion. The UK government hasn't gone beyond its standard non-comment. It hasn't said whether it asked the Americans anything, or whether it was even consulted before the aircraft left.
Rotations happen at Mildenhall all the time. That's normal. What isn't normal is the timing. Right after Fairford. Right after the FPCON upgrade. Right after a summer where Iran named British bases as targets.
So is this routine. Or is Iran building towards something against American forces on British soil.
Nobody in government, British or American, is saying which.
