The Sinn Fein president, Mr Gerry Adams, said yesterday a "major breakthrough" move sufficient to definitively resolve the weapons issue was put forward by the IRA before the Northern Secretary's move to suspend the Assembly.
Mr Adams said he had a "clear understanding" that the development had resulted in a positive report from Gen de Chastelain's decommissioning body. He called on Mr Peter Mandelson to release this second report.
Mr Mandelson had "thwarted" the proposition by suspending the institutions on the basis of "the atmosphere of ultimatum" set by Mr Trimble's threat to resign as First Minister.
"The core of the proposition, which resulted from shuttle diplomacy by senior members of our party moving between the governments, the UUP, the White House and the IRA, was a clear context in which the IRA would deal with the issue of weapons in a way which would maintain, or boost or establish public confidence that this issue was being dealt with properly, definitely and forever," said Mr Adams.
"When set alongside the IRA's recent assertion that the peace process is under no threat from it, and that its guns are silent, this new development takes on an enormous significance and can, if there is political will and good will, finally resolve this matter."
He said if Mr Mandelson wanted to achieve a solution he should immediately rescind the legislation to suspend the institutions.
"I anticipate a positive de Chastelain report that will reflect this development and I believe this will clear the way to end this crisis.
"Can I say that as far as Sinn Fein is concerned we were only prepared to pursue this on the basis that the issue of arms will finally be disposed of, and whatever the outcome of that effort, this issue must no longer be used as a block on progress within the peace process."
Mr Adams said the two governments had been kept abreast of every development in the initiative over the last two weeks. "There is no question about them being surprised by this or this coming too late."
He said the current situation was now difficult to advance and it was up to the IRA whether the proposals remained on the table with the suspension of the institutions.
Mr Adams stressed he would not have said the proposition was a "major breakthrough" if it had not merited the description, but he stressed that it may not have provided a solution "exactly" on the terms demanded by unionists or the British government.
"But in terms of peace making and conflict resolution it would have had the objective of dealing with this issue definitively and conclusively."
He denied that the proposition represented an attempt by Sinn Fein to deflect blame from it for the suspension. "The peace process is bigger than us, than anyone in the UUP, the NIO or 10 Downing Street. People will blame the unionists or blame the republicans depending on what their prejudices may be.
"Despite our instinct we actually moved to deal with it [decommissioning] in a way which sought to meet the problems of unionism, the problems that David Trimble had. We had moved to a point where we had the breakthrough that I described and now that has been set to nought."
The Sinn Fein Minister of Education, Mr Martin McGuinness, said Mr Mandelson had done a great disservice by "caving in" to UUP demands. He had effectively decommissioned the institutions.