A teenager is in a critical condition in hospital, and an 18-year-old has been arrested after a vehicle left the road in rural Northumberland.
Emergency services were called to Moorhouse Crossroads near the village of Edlingham on Monday evening to reports that a silver Nissan Pixo had collided with a tree.
A 17-year-old female passenger were taken to hospital with life-threatening injuries.
The 18-year-old driver was treated in hospital for a shoulder injury but later released, and subsequently arrested on suspicion of causing serious injury by dangerous driving.
Northumbria Police has appealed for anyone who may have seen the vehicle on Monday evening to contact police.
A spokeswoman said: "This was a very serious collision and a teenage girl continues to fight for her life in hospital.
“As you can imagine, this is a distressing time for her family and we are carrying out enquiries so we can find out exactly what has happened."