U.S. Air Force personnel at RAF Lakenheath in Britain responded to "suspected unauthorised drone activity" on Friday evening, a U.S. Air Force spokesperson said. No personnel, aircraft or infrastructure were affected, the spokesperson said. "We continue to work closely with our host nation counterparts to ensure the safety and security of our U.S. service members, U.S. and host nation civilians, contractors, and all of our families," the spokesperson added. The British Ministry of Defence was not immediately available for comment.

The incident comes amid heightened security around U.S. bases in Britain. In recent weeks, the United States has moved bombers that had been used to strike Iran out of Britain, and switched large refuelling aircraft from Britain to Germany. The bombers left RAF Fairford on security grounds after a group of men approached the base in white vans in the middle of the night.

Two men were charged last month in connection with that incident, with prosecutors alleging one of them had tried to assist Iranian intelligence in Britain. The Wall Street Journal has reported that the refuelling aircraft were moved because of a threat from Iran.

RAF Lakenheath in Suffolk hosts U.S. Air Force F-35A Lightning II squadrons.