Police have closed down a quad biking and motocross event after one rider was killed and another seriously wounded in separate incidents.
The event was being held at the Hardwick Hall Hotel, near Sedgefield, County Durham.
The first incident happened just after 1pm and involved a male rider who came off his bike and suffered critical injuries.
He was taken to James Cook Hospital in Middlesbrough by air ambulance but was confirmed dead soon after arriving.
The second rider, a female in her early 30s, suffered serious injuries in another incident just before 2.10pm.
She, too, was taken to James Cook Hospital by air ambulance.
Her condition is unknown.
A police statement said they took the decision "on safety grounds to close down the privately-run event, which involved around 100 participants and 300 spectators".
Supt Mick Bird added: "We are understand the formal investigation is likely to be led by the local authority but we are carrying out initial enquiries into the circumstances
"With two very serious incidents within little more than an hour, we felt there was little choice but to bring the event to a close."