A fourth man has been arrested by Gardaí investigating a serious assault on a Canadian tourist in Dublin City Centre last weekend.

The tourist, aged in his 40s, remains in a serious condition in hospital after the incident on O’Connell Street and Cathal Brugha Street in the early hours of Sunday morning.

Gardaí arrested a man in his 20s as part of their investigation this morning and he is now being held at a Garda station in Dublin.

He is the fourth man to be arrested in connection with the attack.

A man in his 30s who was arrested on Monday has been released without charge with a file to be prepared for the Director of Public Prosecutions.

Earlier that day, Gardaí arrested two men – one his 20s and one in his 30s.

The younger of the two has appeared in court where he was refused bail.

The man in his 30s was released on Monday afternoon.

Gardaí are continuing to appeal for witnesses to the assault.

They are particularly interested in talking to anyone who was were in the Cathal Brugha Street area, near the Living Room Bar, between 12.40am and 1am or on O’Connell Street Upper near the Spar Shop, Funland or Tourism Office, opposite the Spire, between 12.40am and 1am.

Anyone with camera footage is asked to make it available to Gardaí.