The Sinn Fein president, Mr Gerry Adams, has described Mr David Trimble's hardened stance on IRA decommissioning as a "stupid and unattainable" demand.
Speaking at a meeting of Sinn Fein party activists in Castlebellingham, Co Louth, yesterday, Mr Adams said the Ulster Unionist Council's adoption of Mr Trimble's six-point plan represented an "ungracious rejection of the IRA initiative" on arms inspections.
Mr Adams said Mr Trimble had failed to tackle the problems presented by the anti-Belfast Agreement wing of the Ulster Unionist Party and was close to breaching the terms of the agreement by threatening to exclude Sinn Fein Ministers from the North-South Ministerial Council.
"He has chosen to step outside that agreement and if he follows through on his threat he will be in breach of the agreement, and in contravention of his pledge of office and of his ministerial code," he said.
"Sinn Fein does not hold Executive position by dint of patronage from the UUP. We have a mandate and the citizens we represent must have exactly the same rights as all other citizens."
Mr Adams said he had been in contact with both the British and Irish governments yesterday but said the "primary responsibility" for upholding the terms of the Belfast Agreement lay with British Prime Minister, Mr Tony Blair, and his colleagues.
"They cannot allow a unionist veto," he said.
He appealed to the Taoiseach, Mr Ahern, to use his influence with Mr Blair to persuade him to continue to implement the terms of the agreement.
The Sinn Fein Minister, Mr Martin McGuinness, said the party intended to send a Minister to this week's proposed meeting of the North-South Council, despite Mr Trimble's threat.
"We will be endeavouring to attend that meeting," he told the BBC's On The Record programme. "I'm not going to be treated as a second-class Minister by the leader of the UUP - or, indeed, by Peter Mandelson or anyone else."
Mr McGuinness called for an immediate meeting of the Executive to discuss the UUC's decision.
He claimed the anti-agreement wing of unionism had succeeded in bringing Mr Trimble over to its side. Unionists and British politicians opposed to the peace process must not be allowed to "emasculate" the agreement. Mr Gerry Kelly, Sinn Fein Assembly member for North Belfast, described Mr Trimble's threat to bar Sinn Fein ministers from the North-South Ministerial Council as a "recipe for disaster".
"We want the gun moved out of Irish politics but this is the wrong way to do it. If Mr Trimble thinks threatening to pull down the institutions will help, he is wrong," he said.
"The institutions are the alternative to violence. He is threatening to withdraw the alternative. . . . No nationalist, republican or IRA person is threatening to pull down these institutions," he said.
"The combined effects of the British government's approach to the implementation of the agreement and the UUP's tactical engagement are leading to a timetable for disaster," he said.
