There were three separate stabbing incidents in Dublin overnight.
One man, believed to be in his late 20s, was found with a serious knife wound to his right leg at Oaklands Avenue in Swords at around 3am, a Garda spokesman said.
He is believed to be a non-Irish national, possibly eastern European. The man was taken to Beaumont Hospital and later transferred to the Mater. His injuries are understood to be serious.
In a separate incident, two men were reportedly stabbed in a row at Tubber Lane in Lucan at around 4.30am. However, a Garda spokesman said no formal complaint had been received by gardaí about this incident.
The Garda spokesman said a 19-year-old man was also stabbed in the back in an incident at Mackintosh Park in south Dublin and was taken to hospital for treatment. His condition is not believed to be serious and gardaí are investigating the matter.