Royal Air Force aircraft had two close encounters with suspected drones during military exercises over the North Sea in February, the British newspaper The Telegraph reported on Friday.

The incidents occurred days apart during an air-to-air refueling exercise and simulated aerial combat training, with both objects spotted above 10,000 feet.

In the first incident, an RAF Airbus Voyager tanker was refueling a Typhoon fighter near Cromer, Norfolk, when an unidentified object passed so close that the tanker pilot reflexively ducked. The commander reported the encounter to military controllers, according to the newspaper.

On Feb. 23, a Typhoon pilot practicing aerial combat with another fighter near Humberside spotted a black circular object passing approximately 300 feet above the aircraft.

The pilot alerted the radar controller overseeing the exercise, who subsequently relayed the sighting to North Yorkshire Police. Multiple external investigations are ongoing. It remains unclear whether the objects were hostile.

A Ministry of Defence spokesperson said enhanced vigilance and improved detection capabilities had strengthened its ability to identify, record and assess potential drone activity.

The spokesperson said Britain was investing more than £2 billion ($2.67 billion) in broader air defense and counter-drone capabilities, including upgrades and maintenance for the Typhoon fleet.

The ministry added that reported drone sightings were not necessarily hostile and that it had measures available to respond if the activity was assessed as posing a credible threat.