A seven-year-old boy has died following an accident involving a steam traction engine and trailer at an open-air museum in County Durham.
Police and an ambulance crew were called to Beamish Museum, in Stanley, just before 15:00 BST.
The boy was pronounced dead at the scene after suffering serious head injuries.
The engine driver was also taken by ambulance to University Hospital of North Durham suffering from shock.
Durham Constabulary said it was conducting a joint inquiry with the Health and Safety Executive.
Insp Steve Dowdle said: “The engine driver will be spoken to by police at an appropriate time and is being treated as a witness.
“The identities of those involved are not being released, but it is understood that neither of them were visitors to the museum.
“Detectives and roads policing officers are at the scene to establish exactly what took place and the Health and Safety Executive is also at the scene.”
The museum’s director Richard Evans said: “We are naturally shocked and our thoughts are with the boy’s family at this time.
“We took an immediate decision to close the museum for the rest of the day as we support the joint investigation.”
The open air museum aims to recreate life in a typical mining village in north-east England in 1913.