Ten people have been arrested in Northern Ireland after a series of searches targeting so-called New IRA suspects on both sides of the Border.
The operation by the Police Service of Northern Ireland and gardaí is one of the biggest operations of its kind for a number of years.
In the Republic, Garda search teams carried out at least six searches in counties Dublin, Laois, Cork and Kerry.
In reply to queries from The Irish Times, Garda Headquarters in Phoenix Park, Dublin, confirmed the operation, saying the searches in the Republic were being conducted "in support of an operation led by the Police Service of Northern Ireland".
It added: “The searches in this jurisdiction are being carried out at locations in Dublin, Laois, Cork and Kerry and are part of ongoing operations to combat the activities of the New IRA.
“The searches are being conducted by members of the Special Detective Unit assisted by local gardaí and Regional Armed Support Units.”
The PSNI also confirmed its part of the investigation into the New IRA, with the operation in the North more significant in scale than that in the Republic.
While no arrests had been made in the Republic early on Tuesday afternoon, some 10 suspects had been arrested in Northern Ireland.
“Officers from the Police Service of Northern Ireland have made a number of arrests under the Terrorism Act across Northern Ireland today in connection with an ongoing investigation into the activities of the New IRA,” the PSNI said in a statement.
The operation comes at a time when the New IRA is understood to be gaining in strength and the security threat it poses increasing.
In February, Sinn Féin vice president Michelle O’Neill said the New IRA was planning an under car bomb attack on a Sinn Féin member.
She explained at the time that she had been advised of the threat by police in Northern Ireland.
Ms O'Neill, Stormont's Deputy First Minister, said officers had warned that dissident republicans were planning to attack her and the party's policing spokesman Gerry Kelly.
It came in response to the pair’s attendance at a Police Service of Northern Ireland recruitment event.
The New IRA was also behind the murder of journalist Lyra McKee, who was shot dead in the Creggan in Derry in April last year.