The Ulster Unionist Party yesterday said the IRA's refusal to disarm indicated a lack of commitment to the peace process.
As senior UUP representatives engaged in bilateral meetings with members of a Sinn Fein delegation throughout the day, the UUP issued a statement demanding a start to decommissioning, saying that the UUP had done everything required under the Belfast Agreement.
"The process of decommissioning must start now. Sinn Fein must show their commitment to the word and spirit of the agreement by removing the implicit threat of violence that the IRA presents."
"The Ulster Unionist Party has done everything required of it under the agreement. Every area of the agreement apart from the decommissioning section has been progressed," the statement said.
There was a "clear linkage" drawn in the Belfast Agreement between decommissioning and the exclusion or removal from office of parties who failed to show a commitment to peaceful and democratic means.
"The existence of a fully armed and active IRA, without so much as a credible and verifiable start to a process of decommissioning, is an obvious sign of this lack of commitment."
Paramilitaries had failed to realise the extent of public resentment of the early release of prisoners and did not respond to the releases with a gesture on decommissioning, the statement added.
But speaking yesterday before talks between his party and the Ulster Unionists, the Sinn Fein chairman, Mr Mitchel McLaughlin, said any demands for decommissioning this week were "unrealistic and unachievable".
He said it was time for everyone to work collectively to complete the implementation of the Belfast Agreement. "Too many people out there have invested all of their hopes in the parties and have given their mandates to the parties represented here. They expect them to implement the Good Friday agreement."
Sinn Fein had been clear about where it stood on decommissioning. It would try to make other parties realise that demands for an arms hand over "were always unrealistic and in the context of the work that we have to do this week are certainly unachievable".
The SDLP Assembly member for Fermanagh and South Tyrone, Mr Tommy Gallagher, said the only way to solve the impasse was for each side to take seriously the concerns of the other.
An accommodation had to be found to allay the fears of "those who feel vulnerable to paramilitary violence and those who lack confidence in the reforming capacity of the agreement, particularly in the spheres of demilitarisation and the reform of the RUC".
The Alliance Party has presented Dr Mowlam with a document outlining a number of options open to the parties for clearing the decommissioning hurdle. The party leader, Mr Sean Neeson, said the parties had reached "crunch time" and he urged them to "put the people of Northern Ireland first above all other considerations".
"The arrival of the Prime Minister and the Taoiseach can help, but we can't keep on going back to them to move this forward. If we don't move forward this week, Northern Ireland will be in big difficulties," he added.
Arriving at Stormont yesterday, the Northern Secretary said she believed this would be a difficult week, but not a "make or break" situation. Dr Mo Mowlam said the British Prime Minister, Mr Blair, and the Taoiseach, Mr Ahern, would have no "miracle" or "magic formula" with them when they arrived in the evening for negotiations with party leaders.
"It's in the hands of the pro-agreement parties to make it work. If it was in the hands of the anti-agreement parties, then I would worry." The North's Development Minister, Mr Paul Murphy, said it was "vitally important" to resolve the impasse and to set up the executive before Easter.
"Everybody knows when we come back after Easter it is a difficult time politically in Northern Ireland with the marching season, There is the European election in front of us. That is why it is so vitally important that we try to resolve this problem before we go away for Easter," he said.
"I don't know how it will pan out this week," he said, adding that the British government did not have a plan other than to indicate "the prize is enormous".
