The death of the son of a US Air Force Lieutenant Colonel from gunshot wounds was a "tragic accident", a US Air Force spokesman has said.
The 13-year-old boy was injured at a house in Souldern, near Bicester, Oxfordshire, on Sunday morning and died at the John Radcliffe Hospital in Oxford earlier on Monday with his family by his side.
His father is understood to be based at the USAF base in nearby RAF Croughton.
The USAF spokesman said: "The 13-year-old son of an active duty US Air Force lieutenant colonel assigned to an academic exchange programme at Oxford University has passed away after a tragic accident.
"All possible support and comfort is being provided to the family. During these difficult times we respect the family's request for privacy."
Thames Valley Police, which is investigating the death, said it was not treating the incident as suspicious although a spokesman added: "The exact circumstances are yet unclear".
A South Central Ambulance Service spokeswoman said: "We got a call at 10.06am yesterday to Souldern following reports that a 13-year-old male had suffered head injuries with a shotgun."
A police spokeswoman said: "Thames Valley Police is continuing in its inquiries to help the family establish what has happened.
"It is believed there is no third-party involvement and so no one is being sought in relation to the incident."
The teenager's death has been referred to the coroner for Oxfordshire.