Mr Tony Blair faces vital and potentially difficult meetings with the Taoiseach, Mr Ahern, today and the Sinn Féin president, Mr Gerry Adams, tomorrow amid calls in Belfast not to suspend the Stormont institutions.
Education Minister Mr Martin McGuinness called on the British prime minister to stand by the Belfast Agreement and the Executive and Assembly which it established. "Tony Blair should defend the agreement and he should defend the institutions established under the terms of the Good Friday agreement," he said.
"If David Trimble wants to walk away from the people's institutions, then that's a matter for him." He said unionists were wrong to believe they could renegotiate the agreement should London try to resurrect the political process after any suspension.
"Sinn Féin isn't going to toddle off into the sunset. We are going to be here because the people we represent no longer regard themselves as second-class citizens." He again strenuously denied republicans had been involved in intelligence gathering. "I am totally and absolutely opposed to anyone doing anything of an illegal nature which would undermine the people's institutions, undermine the Good Friday agreement and undermine a peace process that I and other Sinn Féin leaders have worked very, very hard to build."
The SDLP deputy leader, Ms Bríd Rodgers, criticised republicans for acting in a manner she said was prejudicial to the very trust needed to sustain the political process. Ms Rodgers told the BBC many nationalists were dismayed with recent events and were angry at how alleged activities of some republicans had damaged the agreement.
"I am very disappointed that they are failing to address the real issue now - that real questions have been raised about their activities and they are simply ignoring the effect that that is having on trust," she said. "I think it is a tragedy that those who supported the agreement on the unionist side - certainly after the events of the weekend - we are losing their support." She said the damage done this week could be irreparable.
Anti-agreement unionists, led by the DUP, said it was inevitable the Executive would collapse and "end in tears".
"That day of tears is coming closer," said Mr Ian Paisley junior. "At every stage our aim has been to achieve the removal of armed terrorists from government. If our resignations set in place a chain of events that leads to the removal of Sinn Féin from government, then you know our party will be at the front of that chain."
His father, Mr Ian Paisley, DUP leader, accused the Northern Secretary of mishandling the intelligence-gathering affair and called for Dr John Reid's resignation. He also accused Mr Trimble of shifting responsibility for excluding Sinn Féin on to the British government and criticised the UUP for not quitting its Executive seats.
"We have another fudge from Mr Trimble today and we now see that he isn't prepared himself to take the initiative." He believed a motion to exclude Sinn Féin would put pressure on the SDLP to declare where they stood.
But Sir Reg Empey denied the UUP had fudged anything. He rounded on the DUP claiming they had followed where his party had led. "They don't get involved in any negotiations and then complain about the outcome. They now say they are going to try and renegotiate, when in fact they had the opportunity to negotiate, they ran away," he said.
The UUP would remind Mr Blair and Dr Reid of their obligations to act against republicans if there were breaches of the IRA ceasefire, he said.
"We will be asking the Secretary of State and the prime minister what it is that they intend to do, because it is they who are primarily responsible for this."