The former Noraid publicity director, Mr Martin Galvin, has told a gathering of anti-agreement republicans that they would force the British to leave Ireland "however long it takes".
Mr Galvin was speaking on Saturday at the a.g.m. of the 32 County Sovereignty Movement in Dundalk, Co Louth. Eighty delegates from both sides of the Border, Britain and the US attended.
Speakers condemned the Belfast Agreement and accused the Provisional IRA of "surrender" on decommissioning.
There was a continuous Special Branch presence outside the conference in the Carrickdale Hotel. Among those present was Ms Bernadette Sands-McKevitt; an Omagh councillor and former Sinn Fein member, Mr Francie Mackey; and the former IRA hunger-striker, Ms Marion Price.
Security sources say the Sovereignty Movement is the "Real IRA's" political wing, a claim the group denies. Those injured and bereaved by the Omagh bombing, carried out by the "Real IRA", had condemned the decision to hold the conference.
Addressing the crowd, Mr Galvin said: "You were all supposed to have been dealt with. People like you were no longer supposed to be around. You have been vilified and demonised in the media. You were expected to follow your former colleagues into Stormont or else to simply walk away and do nothing.
"But you haven't done that. I am confident we can put republicanism back on track. We will never accept British rule in Ireland no matter who signs up to it or sits as ministers in Stormont. We will continue to challenge the British for as long as it takes to end their rule in Ireland for ever."
Ms Price claimed Sinn Fein had accepted the unionist veto and now had identical policies to the SDLP. She accused Sinn Fein leaders of hypocrisy. "They fought the Assembly elections on the slogan `No return to Stormont'. Presently their members enjoy all the perks and trappings in that symbol of tyranny and oppression.
"For almost 30 years they said the six-county statelet was unworkable while today two of their members are British Crown ministers administering British rule in a political entity which hundreds of volunteers sacrificed their lives attempting to destroy."
Ms Price claimed that by allowing arms inspectors to visit its dumps, the IRA was effectively decommissioning, which was "both criminal and treacherous in the extreme".
She claimed the Sinn Fein leadership was motivated by an "egotistical lust for power". The Sovereignty Movement could never be accused of political opportunism or treachery.
The meeting was addressed by Mr Martin Duffy, a recently released "Real IRA" prisoner from Lurgan, Co Armagh. He said the situation in Maghaberry jail, where republicans and loyalists are not segregated, was extremely dangerous.
The chairman of the movement, Mr Francie Mackey, opened his address by saying, "We haven't gone away, you know."