The A5 in Northamptonshire between Weedon and Church Stowe, is closed following a serious road traffic collision, say police.
An air ambulance was called to take one person to hospital with serious injuries. A number of other people were treated at the scene.
Four vehicles are thought to have been involved in the collision which took place at 5.50am (Wednesday, November 29).
Emergency services remain at the scene of the collision and at this stage it is not known when the road will be re-opened.
Motorists are advised to avoid the area during this time.