A Red arrows plane has crashed at an RAF base with the pilot reportedly ejected from the aircraft.
The air ambulance has been scrambled to RAF Valley on Anglesey, North Wales.
The Ministry of Defence confirmed it was a Hawk aircraft and an emergency ambulance crew was sent to the scene at about 13:30 Pm on Tuesday.
It is understood two people were on board the aircraft.
RAF Valley is a base used to train UK fighter pilots and aircrew for mountain and maritime operations.
In total, about 1,500 service personnel, civil servants and contractors work at RAF Valley.
An RAF spokesman said: “We are aware of an incident today at RAF Valley involving a Hawk aircraft. We are investigating the incident and it would be inappropriate to comment further at this stage.”