The DUP has reacted angrily to a decision by the SDLP to side with Sinn Fein in order to block its Assembly motion of no confidence in Mr Martin McGuinness.
Mr Peter Robinson, the deputy leader of the DUP, claimed the SDLP preferred to support members linked to paramilitaries than uphold democracy.
The "petition of concern" lodged by the two parties means today's vote on the DUP motion needs a cross-community majority of 60 per cent of the chamber and 40 per cent of both nationalist and unionist benches to succeed.
"The SDLP are indistinguishable from IRA/Sinn Fein within the Assembly and are more prepared to back the terrorist representatives than support those who believe in democracy," said Mr Robinson.
He stressed that the motion, tabled following Mr McGuinness's admission that he was second-in-command of the Derry IRA on Bloody Sunday, would be debated as planned.
The SDLP's deputy chief whip in the Assembly, Mr Alastair McDonnell, confirmed his party joined forces with Sinn Fein to ensure the cross-community vote. "This motion of no confidence in Martin McGuinness is another silly attempt by the DUP to destabilise the Executive." Meanwhile, the Sinn Fein vice-president, Mr Pat Doherty, yesterday described the UUP leader, Mr David Trimble, as the "best ally" the DUP and other anti-agreement unionists could have.
His comments came amid speculation that the North's political institutions may be suspended for a second time following the British general election. "Every crisis we have faced in the last three years can be laid at the door of Mr Trimble. Every threat to the peace process has come primarily from unionist intransigence and bluster," Mr Doherty said.