Republican groups have been kept under close watch by gardaí and military intelligence
Garda and military intelligence services have kept republican political group Saoradh under close surveillance since its creation three years ago.
The organisation, which has close links to the New IRA, was widely condemned after holding a march in the capital as part of an Easter 1916 commemoration.
It went ahead less then 48 hours after the murder of journalist Lyra McKee (29) in Derry on Thursday night.
The young journalist died after a gunman believed to be linked to the New IRA opened fire on a crowd of PSNI officers, journalists and onlookers in the Creggan area.
A similar event in Derry planned yesterday was cancelled, following Ms McKee's killing.
Since its creation in September 2016, Saoradh has had close links with the New IRA, and has been described as the terror organisation's political wing.
These links were evident following the arrest of Kevin Braney, the so-called leader of the New IRA.
At the time of his arrest for IRA membership, Braney served as chairperson of Saoradh Dublin. He was convicted of that charge in 2018 and earlier this year was given a life sentence by the non-jury Special Criminal Court for his role in the murder of Peter Butterly in Co Meath in 2013.
Braney (44) had been a long-term target of the Special Detective Unit, and was charged on two previous occasions for alleged IRA membership, but was acquitted both times.
He was a founding member of Saoradh Dublin in September 2016 and was chairperson until his arrest in August 2017.
Braney has been held in the maximum security Portlaoise Prison ever since.
Sources say that as a result of the evident ties between both Saoradh and the New IRA, State security agencies have been keeping "a close eye" on the political party since its foundation.
"Both groups are brought up together in regular high-level State security assessments. The belief is that they are inextricably linked," one senior source said.
The New IRA itself was formed in 2012, following an alliance of former factions of the Real IRA, the Derry-based Republican Action Against Drugs and republicans elsewhere who had largely remained unaligned up to then because of the level of infiltration by gardaí and the PSNI of the existing dissident groups.
The Real IRA had been highly active in the Derry-Donegal region and had also formed links with the organisation's section in Dublin when it was led by Alan Ryan.
The group, which has around 50 activists and another 200 logistical supporters operating on this side of the Border, has a stronghold in Derry as well as Dublin.