A garda remains in a critical condition in hospital after being assaulted in the city centre over the weekend.
Two gardaí, who were off-duty at the time, were attacked at the junction of Dame Street and Eustace Street at about 1.30 on Saturday morning.
Both were taken to hospital - with one, in his 30s, since discharged.
The other man, aged in his 40s, is receiving treatment in Beaumont Hospital, where his condition is described as critical.
Gardaí investigating the incident arrested in a man in his 30s on Saturday evening. He remains in custody.
A second man, also in his 30s, has also now been taken into custody at a Garda station in the Dublin Region. He can be held for up to 24 hours.
Deputy Lord Mayor Donna Cooney has condemned the attack;
"My thoughts are with the man and his family... To think they were out on a night out, off-duty, and probably on their way home at that stage and for something like that to happen. The level of violence, it's quite shocking really."
