Gardai are investigating 2 separate assaults in Dublin city centre yesterday.
The first incident took place yesterday afternoon at around 3:15 on Parnell Street.
A 42 year old man was attacked and taken to the Mater where his injuries are not life threatening.
Five teenagers who were arrested over the assault have been released without charge and items stolen from the victim were later recovered.
Meanwhile a 42 year old man is in a critical condition after he was assaulted at Montague Place near Pearse St. between 6.50 and 8.30pm.
The man, who suffered serious head injuries was taken to St. James' hospital.
Gardai are appealing for witnesses.
