A 41-year-old Irishman remains in critical condition in Canberra Hospital after been assaulted in Australia,early Sunday morning.

A single blow to the head outside a nightclub left him with cerebral bleeding. Police found him lying unconscious outside a store adjacent to the club at around 5.30am on Sunday.

18-yar-old Daniel Byrne has been arrested after police viewed closed circuit TV footage of the crime.

The man, who was not been named, was treated at the scene before being taken to Canberra Hospital where he underwent emergency surgery for cerebral bleeding. Police have described his condition as “unresponsive”.

“It seems to be a blow from his right arm or elbow,” Det Sgt Matt Innes told reporters.

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“[The victim] sustained what appears to be externally very little. However, on examination at the Canberra hospital, he’s got severe cerebral hemorrhages and he’s had to undergo surgery. . . . We do expect to make some arrests in the next couple of days,” he said .

Staff at the Quick and Go 24-hour convenience store saw a group of five or six men who are believed to have been responsible for the assault and then alerted the police.

Police are seeking a suspect caught on security camera footage.

The Irish embassy in Canberra has been in contact with the victim’s family in Ireland and has offered consular assistance.