Unionists have intensified their hostility towards Sinn Féin following the alleged abduction of Mr Bobby Tohill in Belfast last Friday.
Despite a report in An Phoblacht which claimed that a source, speaking for the leadership of the IRA, had said it did not authorise any action against Mr Tohill, the Ulster Unionists stepped up their protests.
Following Mr David Trimble's ultimatum to the British government in the House of Commons yesterday, senior UUP negotiator Mr Michael McGimpsey said his party had taken the lead on the controversy.
He restated the party's position concerning continued paramilitary activity: "Republicans have had ample opportunity to change their ways. They simply must understand that there is no place for a private army in any normal society."
Mr McGimpsey also accused the DUP of duplicity. "For all their bluster, the last few days have been characterised by vague statements of disgust and half-hearted re-assertions of not talking to Sinn Féin from the DUP. This is not good enough."
The DUP leader, the Rev Ian Paisley, claimed Mr Trimble was trying "to flex his flimsy political muscles". He did not indicate that any Trimble walkout from the review of the Belfast Agreement next week would prompt a wider unionist withdrawal.
He said: "He was the man who allowed Sinn Féin-IRA into government in Northern Ireland on three separate occasions and sustained them there even as they murdered, bombed, beat, exiled, racketeered, smuggled, kidnapped, targeted, trained, gun-runned and recruited.
"Mr Trimble mocked the DUP during the Assembly's election campaign, asking us who would we negotiate with? We have shown that we will not sit down and discuss anything with the representatives of violent republicanism."
In his first major address as DUP European Parliament candidate, Mr Jim Allister accused the Ulster Unionists of "clinging to the wreckage of the Belfast Agreement, and turned on the SDLP calling on Mr Mark Durkan to stand alone from Sinn Féin.
He told a rally in Carrickfergus, Co Antrim: "It's time the SDLP stood on its own feet; there is no future in being the political wing of Sinn Féin."
Mr Durkan said last night that Ulster Unionists were mistaken in threatening to walk away from the talks table, claiming this left the way open for paramilitaries.
He accused the UUP of having a semi-detached relationship with the review process even in advance of the Tohill incident.
"Walking away from the democratic table only gives the paramilitaries the whip hand over political dialogue," he said. He accused republicans of "formulaic evasions" concerning the Tohill case.