A man has been arrested in connection with alleged death threats made to Sinn Fein leader Mary Lou McDonald and Garda Commissioner Drew Harris.
The man, who is in his 20s, was arrested by gardai on Thursday morning.
He is being held at a garda station in Dublin, gardai said.
On Wednesday, Ms McDonald said she had reported a death threat to the gardai.
In a post on X, formerly Twitter, she said: “Last night a threat to kill me was issued online. The individual said he would shoot me dead.
“This represents an escalation of targeted online abuse directed at me over the last year. It is totally unacceptable.
“I have reported this to An Garda Siochana.”