The prospects of the North's First Minister and UUP leader selling the agreement on North-South bodies and ministerial departments to his party were boosted last night after his 100-member executive endorsed the deal.
Mr David Trimble said the party executive had "overwhelmingly" supported it. Members voted for it by 70 votes to 30, which is broadly in line with the percentage of the 700-member Ulster Unionist Council, the UUP ruling body, that supported the Belfast Agreement.
While Mr Trimble was happy with the result, it is understood that two executive members who had previously supported the agreement opposed yesterday's deal at Stormont. Nonetheless it will hearten the UUP leader as he prepares to sell it to his Assembly members. He said the vote reflected the stability of the support for his position.
The Sinn Fein president, Mr Gerry Adams, welcomed the "long overdue progress" in setting up 10 Assembly ministerial departments and six North-South implementation bodies. "There are positive elements of last night's developments and, of course, that there was progress at all is a positive thing in itself," he said.
Mr Adams called for speedy movement to the creation of an executive and a North-South ministerial council. "This will require the same measure of attention and concentration from the two governments which helped secure this progress," he said.
The SDLP leader, Mr John Hume, said he also hoped all elements of the Belfast Agreement could soon be implemented. He believed the IRA and mainstream loyalist paramilitaries were committed to their ceasefires, and to the agreement that requires their political representatives to urge them to decommission by May 2000.
Mr Peter Robinson, the deputy DUP leader, described the deal as "another UUP U-turn". The proposed North-South implementation bodies went beyond the terms of the Belfast Agreement, and the deal "shows once more that the UUP are being dragged inexorably down the Dublin road".
"If they are incapable of resisting republican demands at this early stage what does the future hold? This agreement demonstrates a lack of political judgment and moral courage that has attended the leadership of David Trimble," he said.
The Northern Secretary, Dr Mo Mowlam, congratulated the Northern parties and "the Irish Republic on reaching a genuine accommodation of mutual benefit to North and South".
The Alliance leader, Mr Sean Neeson, welcomed the deal but said he was disappointed that the Assembly was not sitting next week to implement it. He was concerned that equality, community relations and European affairs had been taken over by Mr Trimble and Mr Mallon.
"Some aspects of the deal appear to be more about power brokerage between unionism and nationalism than creating what is best for the people of Northern Ireland. However, it is my hope that devolved powers to the Assembly can still meet the February deadline," he said.
The Women's Coalition in a statement said that because of the recent stalemate people in Northern Ireland could have been forgiven for losing faith in the Belfast Agreement. "This breakthrough will give us all every reason to hope again," the statement said.
"Now that sufficient trust has been generated to develop these structures surely we can move on to form a government," it added.
Mr Ruairi O Bradaigh, of Republican Sinn Fein, said the deal proved that Stormont was stronger while the cross-Border bodies were weakened.
Dr Esmond Birnie, a UUP Assembly member, said that in the deal there was "no essential and irreversible reduction of UK sovereignty". ein and the PUP regarding decommissioning - are not".
Meanwhile, one of Mr Trimble's strongest critics within the UUP said yesterday he was "horrified" at yesterday's agreement.
The East Londonderry MP, Mr Willie Ross, said he feared his party would "reap the fruits" of agreeing to a Sinn Fein executive presence when UUP candidates faced the electorate in the future.