The Rev Ian Paisley yesterday challenged Mr David Trimble to "come clean" with the people of Northern Ireland and declare his "bottom line" on decommissioning.
Mr Paisley said that to his knowledge none of the Ulster Unionist Party officers or Assembly members had been informed by Mr Trimble what his bottom line was.
"He is going into surrender negotiations with no one in his party having a clue what he will settle for. This is a catastrophic situation.
"The background and past behaviour of Mr Trimble cannot instil any confidence in any traditional unionist."
He said no fudge or guarantees by the British or Irish prime ministers or SDLP leader Mr John Hume could be trusted. The only thing that could be trusted was the visible destruction of IRA weapons, he said.
"It is the destruction of weapons first, second and third and there cannot be any diminution. Any diminution would be an act of treachery and outright surrender to Sinn Fein/IRA gangsters," said Mr Paisley.
As Mr Trimble left Hills borough at lunchtime yesterday, he said there was "no sign" that the republican movement was committed to implementing its share of the Belfast Agreement. This was the "primary obstacle" to progress, he said. "We have had no indication yet from the republican movement that they are prepared to commit themselves to carrying out the agreement.
"What we would like to hear from the republican movement . . . is that there is a clear commitment by them to ending the war, to decommissioning, disarming in accordance with the agreement, in the time-scale of the agreement." It must begin in a credible way. "I think we have to be very clear here between form and substance," he added. "There is optimism of course, but at the moment we have not seen any sign that the republican movement is committing itself in a realistic way to carrying out its share of the agreement."
Leaving Stormont at around 6.45 p.m. last night to return to Hillsborough, Mr Trimble said he hoped there would be some progress over the course of the night's negotiations.
"I hope very much when we get there that we will hear that the republican movement is prepared to live up to its obligations in the agreement," he said.
He said his message to republicans was that it was "time for them to square up to what they undertook last year in terms of achieving the disarmament of paramilitary organisations".
There was a "muted" reaction to the IRA statement from UUP members at the talks, according to a UUP source. The omission of the decommissioning issue from the statement was seen as "less than helpful", he added.