The British newspaper, The Guardian, reported yesterday , Sunday, that 3 unknown drones were spotted flying over 3 joint air bases for British and American forces in the United Kingdom .

The newspaper reported that “small unmanned aerial systems” were seen flying over RAF bases in Lakenheath and Mildnall in Suffolk and Feltwell in Norfolk between November 20 and 22 .

The US Air Force, which uses the bases, said it was unclear at this point whether the drones should be considered “hostile” and declined to comment on whether any defensive mechanisms were used, but said it reserved the “right to protect” the facilities .

A U.S. Air Forces in Europe spokesperson said: “We can confirm that small unmanned aerial systems were observed in the vicinity of and over RAF Lakenheath, Mildnall and Vetowell between 20 and 22 November. They were variable in number and varied in size and configuration .”

“The drones were actively monitored and facility commanders determined that none of the incursions impacted base residents or critical infrastructure. To protect operational security, we do not discuss our specific protection measures but reserve the right to protect the facility, ” he added.

He stressed the continuation of monitoring the airspace and working with local authorities and mission partners to ensure the safety of base personnel, facilities and property .

For his part, a British Ministry of Defense spokesman said, “We take the threats seriously and have strong measures in place at defense sites. This includes anti-drone security capabilities. We will not comment further on security measures.”