Letterkenny’s Port Road has been closed to traffic following an overnight incident in which it is believed a person was seriously hurt.
Gardai have sealed off the Port Roundabout and are carrying out forensic examinations.
Eye witnesses say there are blood stains at the scene and there are reports that one person has been taken to hospital.
An area of footpath close to Port Roundabout has been covered in plastic bags.
Gardai are remaining tight-lipped at this early stage of their investigations.
A statement on the incident is expected later.