Unionists are demanding that the British government immediately expels Sinn Fein from allparty talks following the IRA's statement that it has "problems" with the Mitchell Principles of non-violence.
The Sinn Fein president, Mr Gerry Adams, will come under severe pressure to explain his party's position when substantive talks begin at Stormont Castle in Belfast on Monday.
Sinn Fein yesterday insisted it would remain in negotiations, but the Northern Ireland Office described the IRA announcement as "very worrying". A spokesman said Sinn Fein and the IRA were "inextricably linked". If Sinn Fein dishonoured its commitment to the Mitchell Principles, either through its own actions or a return to IRA violence, it would be ejected from the process.
The IRA announcement has put additional strain on the loyalist ceasefire. The fringe loyalist parties yesterday described it as "a nightmare". The statement has also caused difficulties for the Ulster Unionist Party, which meets tomorrow to decide whether to join the Stormont negotiations.
It was believed that moderates and pragmatists in the party held the upper hand and that its executive committee would vote to take part in talks. Although observers believe that position should still hold, the IRA's announcement has undoubtedly strengthened UUP hardliners.
Sinn Fein's national chairman, Mr Mitchel McLaughlin, yesterday said his party planned to be at the talks on Monday. "Sinn Fein is committed to totally democratic and peaceful means in the search for peace. We affirmed the Mitchell Principles on this basis and on behalf of Sinn Fein.
"Sinn Fein is not the IRA and speaks for itself. The IRA statement is not a new position. We have to enter the forthcoming negotiations on a realistic and clear basis."
However, the UUP leader, Mr David Trimble, said the IRA had carried out "a contemptible little trick". It was "totally dishonest" for Sinn Fein to endorse the Mitchell Principles on Tuesday and for the IRA to "attempt to wriggle out of them" two days later. The DUP leader, the Rev Ian Paisley, said that the Provisionals' statement was designed to allow the IRA to kill and bomb while Sinn Fein remained at negotiations. He urged the British prime minister to act immediately.
The Provisionals' announcement weakens the position of the fringe loyalist parties vis-a-vis the hardline Loyalist Volunteer Force led by Billy Wright. The Progressive Unionist Party leader, Mr David Ervine, described the IRA's announcement as disastrous: "It's a nightmare for loyalism and a nightmare for the whole unionist community. It elevates within unionism those who were already distrusting and disbelieving."
The SDLP leader, Mr John Hume, said that the timing of the IRA statement was "peculiar" but he did not believe Sinn Fein should now be expelled from talks. The most important issue was that the IRA had stopped its campaign of violence, he added.