The Sinn Fein leadership reacted angrily to British government amendments to failsafe legislation designed to ease the internal party pressure on the Ulster Unionist Party leader, Mr David Trimble.
The Sinn Fein president, Mr Gerry Adams, and chief negotiator, Mr Martin McGuinness, warned that any changes could be the "greatest blunder" made in recent years by the British government.
Mr Adams said his party had not formally decided whether it would today nominate its two ministers, Mr Martin McGuinness and Ms Bairbre de Brun, to the proposed executive. It was an issue the party would consider overnight.
Mr Adams and Mr McGuinness were responding yesterday evening to British government amendments that would appear to impose a timetable for IRA decommissioning rather than allow it to happen voluntarily.
"For those who may want to deal with the issue of guns - who genuinely want to deal with the issue of guns - they are going about it the absolutely worst and wrong way - totally the wrong way to deal with this matter," said Mr Adams.
Mr McGuinness said "republicans will be rightly angered" as the peace process appeared to be turning into a "decommissioning process" rather than an issue of conflict resolution.
"If this British government allows this to happen it will be the greatest blunder this government has made in the course of recent years," he warned. Asked to elaborate, Mr McGuinness said: "I think it is very clear."
Mr Adams said unionists were imposing the "Orange card". Unionists were not concerned about decommissioning but about "not having a Catholic about the place", he added.
Speaking at Stormont, Mr Adams added, "Let me be very, very clear from this bastion of former unionism that the days of second-class citizenship in this institution, or in our country, or in this state, are over. We are going to be first-class ministers, we are going to be first-class Assembly members, we are going to be first-class citizens on this island."
Asked if Sinn Fein was planning to oppose the amendments legally, Mr Adams said, "We have not considered going to the courts . . . All I can say is that we will oppose this change by whatever way."
Mr McGuinness said the amendments raised serious questions about the independence of Gen John de Chastelain's decommissioning body.