A US airman has been found dead at a base in Norfolk.
A spokesman for the 48th Fighter Wing, based at RAF Lakenheath, said the serviceman was found "unconscious in their work space" at RAF Feltwell, near Thetford.
They have been named as Staff Sgt Ivone Rios, a cyber transport systems maintainer.
Emergency crews tried to revive the airman but were unable. The US Airforce said the cause of death was unknown but an investigation was being carried out.
American warplanes based at Lakenheath in Suffolk will be taking part in night training missions between May 19th and May 22nd.
Senior officers say the night operations are required to maintain aircrew proficiency and ensure pilots remain ready to meet future challenges.
American military personnel have been evacuated from part of the Lakenheath airbase in Suffolk after a suspicious car was found near an entrance.
The A1065 has been closed while explosives experts check the vehicle.
Lakenheath is home to the USAF's 48 Fighter Wing which fly F15 warplanes.