Nationalist politicians have expressed their disappointment at Mr David Trimble's rejection of the proposals put forward by the two governments on Friday.
Mr Martin McGuinness, of Sinn Fein, said Mr Trimble's objections to the proposals would appear to suggest that he had no real intention of sharing power with republicans.
The Mid-Ulster MP, saying Sinn Fein had an absolute commitment to implementing the agreement, accused the Ulster Unionist leadership of having a "tremendous opposition to change".
"It is obvious to me and it will become increasingly obvious to many other people that David Trimble does not want to share power with nationalists and republicans and that he is hiding behind the issue of guns," he said.
Mr McGuinness said he questioned why the UUP had rejected Sinn Fein's overtures if the issue of guns was so important. The real problem for unionists was not guns, but that they were opposed to the change outlined in the Belfast Agreement because it would create a new situation wherein all the people of Ireland would benefit.
Mr McGuinness appealed to the British and Irish governments not to be deflected by the present unionist stance. "If they continue to oppose the establishment of the institutions then all other aspects of the agreement must be implemented," he added. Mr McGuinness said he was doing his best to persuade the IRA to start decommissioning its weapons in accordance with the agreement.
Earlier the Taoiseach, Mr Ahern, said it would be helpful if the IRA issued a statement saying it was ready to start handing over weapons.
Mr McGuinness said he recognised it would be helpful if the IRA issued such a statement. However, he insisted it was a matter for the IRA.
Mr Eddie McGrady of the SDLP said the proposals represented the best way forward. "We can discuss timing and the duration of timing, but we have had 13 months to do that, and now we must move forward and implement the Belfast Agreement in full," he said. The Assembly member and MP for South Down said Mr Trimble's comments could be interpreted as another delaying tactic.
Mr McGrady added that he believed the intentions of republicans to decommission were honourable. "There is a failsafe built into the proposals, stating that if the IRA fails to deliver decommissioning after the executive is established then the process will cease to operate.
"What further cast-iron guarantee does he [Mr Trimble] want? What is really happening is that unionists don't appear to want to compromises at all. They are hooked on this policy of `no guns no government'."