Unidentified drones have been spotted flying over four bases used by the United States Air Force in Britain, prompting the British government to call in military staff to help protect the sites. The U.

The U.S. Air Force reported several incursions occurred in the past week at four bases where the American forces operate.

Unidentified drones are still being spotted over United States Air Force (USAF) bases in England on Wednesday, a USAF spokesperson said, confirming that a fourth base had also been targeted by the week-long airspace incursions.