Gardaí in Killybegs are investigating an assault aboard a vessel in international waters off the Donegal coast yesterday morning.
The incident happened on Liberian registered vessel the Africa Star some 200 nautical miles off the coast.
Sligo-based coastguard Rescue 118 helicopter was scrambled following a request for assistance from UK authorities.
The injured man, believed to be a Ukrainian national, was taken to Sligo General hospital where he is being treated for chest injuries.
READ MORE
His condition is understood to be critical.