A man in his mid twenties has been transferred to hospital in Dublin having suffered injuries in Letterkenny this morning.
The man suffered head and spinal injuries.
Gardai believe his injuries were as a result of a fall and do not suspect he was the victim of an assault.
It is understood that a dispute had started outside a take away on the Port Road shortly before 3.45am.
The injured man, who was not involved in the dispute, is understood to have suffered his injuries as a result of a fall as he ran from the scene.
He was taken to Letterkenny General Hospital before being transferred to the Mater in Dublin.
The area has been sealed off as a precaution, gardai are not seeking witnesses to the incident and are examing CCTV.