Three people have been taken to hospital following a multi-vehicle crash on the A1 southbound, which closed the road in both directions.
Durham Police were called just after 2pm to a crash on the A1 southbound between Washington services and the Chester-le-Street junction involving three or four cars.
Northumbria Police confirmed on their Twitter account at 4.50pm that the A1 has now fully reopened after it was closed in both directions earlier while an air ambulance prepared to land.
The ambulance service was called at 2.04pm and treated four people at the scene, before three people were conveyed to the Royal Victoria Infirmary in Newcastle.
Of the three, a 58-year-old man was taken to hospital suffering from severe head and back pain after suffering a head injury. He is believed to be in a stable condition. The injuries and conditions of the other two people are not known.
An ambulance service spokesman said: "We were called to a two vehicle road traffic collision on the southbound carriageway of the A1.
"Four patients were treated by the ambulance service and three patients have been taken to the Royal Victoria Infirmary."
During the incident Highways England urged motorists to allow extra time for their journey and said on their Twitter account: "If you're travelling A1M near Chester-le-Street there are traffic blocks in operation both ways for an air ambulance landing. Expect delays due to a collision."
County Durham and Darlington Fire & Rescue said on Twitter: "CDDFRS resources are attending a RTC on the A1M in the Chester-le-Street area. Appliances from High Handenhold and Durham have attended.
"One male adult has been released by fire service personnel at the RTC on the A1m using hydraulic cutting equipment."