A number of unidentified drones have been spotted over three airbases in Britain, the United States Air Force (USAF) has confirmed.

The incidents, which occurred between November 20 and 22, saw “small unmanned aerial systems” spotted over RAF Lakenheath and RAF Mildenhall, in Suffolk, and RAF Feltwell, in Norfolk.

The USAF, which uses the bases, said it was unclear at this stage whether the drones were considered hostile.

It also declined to comment on whether any defence mechanisms were used but said it retains “the right to protect” installations.