The US is concerned about Iranian threats against RAF Fairford in the UK, the Associated Press reported, citing a White House source.
A presidential administration official did not rule out a scenario involving the destruction of US military personnel and equipment, though details of any potential operation were not disclosed.
The US military has decided to relocate heavy bombers from Fairford amid the heightened threat level.
In late September, the UK police detained five men near the base on suspicion of plotting a terrorist attack.
