A man sustained serious injuries in a random attack in Dublin city centre.
The victim was assaulted shortly after leaving a pub in the Dame Lane area of the city centre at around 11.30pm on Saturday.
Aged in his late 30s, it is not believed the attack is related to the Gay Pride festivities which took place in the city centre earlier that day.
It is understood he was struck once by his attacker and fell to the street. Gardai do not believe he was known to the assailant.
Detectives hope to speak to the victim as soon as possible.
A suspect, who is known to gardai, was being sought last night for questioning.
The victim was rushed by ambulance to St James's Hospital and later transferred to Beaumont for specialist treatment for head injuries.
Sources said his condition was initially critical but he has since stabilised.
Gardai are appealing for witnesses to the attack.
"Gardai were alerted to the discovery of an unconscious man by a member of the public at about 11.30pm on Saturday," said a spokesman.
"The man, in his late 30s, was found with serious head injuries close to the entrance of a pub on Dame Lane.
"Medical assistance was sought and the man was taken to hospital, where he remains in a serious condition," said the garda spokesman.
Gardai are appealing for anyone who was in the Dame Lane area between 11pm and midnight on Saturday to contact them at Pearse Street on 01 666 9000.
A Dublin Fire Brigade source said its ambulance service dealt with a number of assaults in the city centre on Saturday night.