Gardaí in Killybegs are investigating an alleged stabbing which occurred on a vessel off the coast of Donegal.
The Sligo-based rescue helicopter was tasked to the scene after the incident was reported in the early hours of Friday morning.
A crew member was brought to Sligo General Hospital and then transferred to Galway University Hospital.
The man is believed to be in a critical condition after suffering a stab wound.
The incident occurred in international waters and the vessel is now in Killybegs where gardaí are investigating the incident.