A man has been taken to hospital following a collision at Lifford Bridge this morning.
The crash, between a Scania lorry and a BMW, occurred just after 9am.
The driver of the BMW, whose condition is understood to be serious, was taken by ambulance to Altnagelvin Hospital.
The road between Lifford and Strabane is closed, with traffic diverted via Clady.
Anyone with information is asked to contact the Gardaí or the PSNI.