Sinn Fein is demanding an emergency meeting of the Northern Ireland Executive to discuss plans to ban its two Ministers from North-South Ministerial Council meetings. The party expressed its "deep concern" about the development and urged both governments to take action to defend the Belfast Agreement.
It is understood Sinn Fein's Health Minister, Ms Bairbre de Brun, who is due to hold talks with the Minister for Health, Mr Martin, at a health and food safety meeting in Enniskillen, Co Fermanagh, on Friday, is anxious for the event to go ahead.
A senior Sinn Fein source last night indicated no change to her schedule. "Our Ministers will continue doing their jobs and will not be put off by David Trimble's antics. That meeting is not just a matter for David Trimble, it is a matter for Dublin also."
Ms de Brun and Sinn Fein Education Minister, Mr Martin McGuinness, have written to Mr Trimble and the North's Deputy First Minister, Mr Seamus Mallon, requesting an emergency Executive meeting.
"Sinn Fein is deeply concerned at the path David Trimble has chosen to pursue," Mr McGuinness said. "Mr Trimble has not stood up in defence of the Good Friday agreement. Instead, he has adopted an approach that is in clear breach of the spirit and letter of the agreement.
"It is not for David Trimble or any other unionist leader to set limits on the rights and entitlements of nationalists and republicans. There can be no unionist veto."
Mr Trimble, who is in Spain for a conference on regional government, predicted the current system of devolution in the North would prove stronger than the old Stormont. The onus to end the current political crisis lay firmly with Sinn Fein and the Provisional IRA, he added. "They have spent the weekend crying foul but they will have to start delivering on their agreement promises."
SDLP Agriculture Minister, Ms Brid Rodgers, described the political situation as very serious. The Ulster Unionist Council did not have the right to "unilaterally decide" who attended North-South Ministerial council meetings.
"Nobody has the right to rewrite the Good Friday agreement, not the British government, not the UUP, not Sinn Fein. The SDLP will insist that the will of the people be upheld."
UUP Arts Minister, Mr Michael McGimpsey, accused Sinn Fein of hysterical overreaction to his party's decision. "We are determined to make the agreement work. When the IRA begins to do what the IRA promised, these sanctions are easy to lift."
UUP deputy leader Mr John Taylor, who did not attend the UUC meeting, supported the sanctions against Sinn Fein. While he would have preferred a Christmas deadline for Provisional IRA decommissioning, he could accept a January deadline which, he said, Mr Trimble had agreed.