The Sinn Fein president, Mr Gerry Adams, has appealed to unionists not to "hard-ball" but to work with nationalists to resolve the decommissioning impasse, which is threatening to bring down the North's Executive.
He also warned that a weapons handover would never occur if the Ulster Unionists now decided to walk away from the Executive.
"I would appeal to unionists not to hard-ball or to go down to the wire on this issue, to continue to work with us and others to resolve the issue in the same way as we have worked with them to resolve other issues," Mr Adams told the BBC's Breakfast with Frost.
"It is clear that if this process collapses, it is clear that if the UUP walk out of the process, it is clear that if the British government is spooked into suspending the process on a unionist threat to walk out, decommissioning is never going to happen."
The IRA was likely to withdraw all co-operation with Gen John de Chastelain's decommissioning body if unionists caused the Executive to disband.
Mr Adams said that while he was totally committed to resolving the current impasse and fully understood the unionist demand for decommissioning, he simply could not give any guarantees on the issue, nor was it his responsibility to do so. Asked whether he could guarantee some decommissioning by the May deadline, he said: "No, I can't, and it isn't up to me to guarantee it."
He wanted to continue his partnership with Mr Trimble, he said, and was working behind the scenes to resolve the situation. He believed Gen de Chastelain's report would indicate some progress, if not necessarily of the kind which unionists would consider satisfactory. Asked whether he thought the IRA would return to a campaign of violence, Mr Adams said the political vacuum created by the collapse of the institutions could create a dangerous situation, given the number of armed groups still engaged in the conflict.
The Deputy First Minister, Mr Seamus Mallon, said there was no excuse for the IRA not to contribute to the peace process.
"The clear understanding was that the IRA would reciprocate, that they would follow out their part of the bargain . . . and that was to deal with decommissioning," he told Sky News's Sunday with Adam Boulton.
He said there were three options regarding Gen de Chastelain's report: a very positive report which nobody expected, a totally negative one, or "something in between".
"In that case, the general would still hold out some hope that decommissioning will take place and possibly add to that some type of time-frame. The question is, would that third type of report be sufficient?" Mr Mallon asked.