Sirens sounded at two air bases in eastern England on Friday evening following suspected drone activity, local media reported.
The Daily Mail reported that residents near Royal Air Force (RAF) Lakenheath in Suffolk and RAF Feltwell in neighboring Norfolk heard sirens at about 5.30 pm local time (0430GMT), which some compared to wartime warnings.
Locals said a loudspeaker announcement in an American accent urged people to remain indoors and seek shelter.
Video footage shared by the Daily Mail showed sirens sounding across darkened residential gardens.
The report said the US Air Force confirmed the Lakenheath alarm was linked to "suspected unauthorized drones," and that no personnel, aircraft, or infrastructure were affected.
Separately, a spokesperson for US European Command said the suspected drone incursion caused no damage, according to Axios news website.
"We continue to work closely with our host nation counterparts to ensure the safety and security of our US service members, US and host nation civilians, contractors, and all of our families," the spokesperson said in a statement cited by Axios.
The incident followed the evacuation of at least 12 aircraft from RAF Mildenhall in Suffolk days earlier over a security threat tied to Iran, according to the report.
