A 22-year-old man is in a serious condition in hospital, following an assault in Tuam in Co. Galway overnight.
The attack happened on the Milltown Road at around 3.30am.
The man sustained severe head injuries and was rushed to the Beaumont Hospital in Dublin, where his condition is described as serious.
An 18-year-old man has been arrested.
He is currently being detained at Tuam Garda Station.