The anti-agreement Ulster Unionist MP, Mr Jeffrey Donaldson, has called for a meeting of the party's ruling Ulster Unionist Council in the next few weeks to decide on a motion that could threaten Mr David Trimble's leadership of the UUP.
Mr Donaldson said the UUC should be convened to vote on a motion demanding that the First Minister and his three Ministers withdraw from the Executive in the absence of IRA decommissioning.
Mr Donaldson's move is being viewed by pro-agreement Ulster Unionists as tantamount to a leadership challenge to Mr Trimble. Were the motion to be carried, there would be pressure on Mr Trimble to resign as Ulster Unionist leader.
A special review group on decommissioning established after the last UUC meeting in May issued a statement on Tuesday complaining that the failure of the IRA to disarm and the proposed policing changes had inflicted "massive damage to the political process".
A Trimble aide said on Tuesday in advance of this statement that this would be the opening shot in the attempt to oust Mr Trimble as leader.
The East Derry MP, Mr William Ross, maintained the pressure from the No side by saying Mr Trimble's policy had led the UUP to the brink of electoral disaster. Sir Reg Empey, the pro-agreement UUP Enterprise Minister, also called for a move on arms. He claimed, however, that the No bloc within the party still had no alternative to the agreement. "What do you replace the agreement with? Do you want to go back to war? Do you want to go back to the bombings? . . . People have got to keep their heads and their nerve," said Sir Reg.
The UUP deputy leader, Mr John Taylor, also warned that without progress on arms, policing and flags the Executive and Assembly would be in "dire straits" by Christmas.
The Sinn Fein president, Mr Gerry Adams, said in Dublin yesterday that the claims of a possible leadership challenge against Mr Trimble were "artificial".
He said "taking the gun out of Irish politics" was a very fundamental and core part of the Belfast Agreement, but the current unionist demands were not the way to go forward.
