Mr David Trimble has told his party's ruling body that there will be IRA decommissioning.
The Ulster Unionist Party (UUP) leader also criticised anti-Belfast Agreement elements within the party and within unionism generally, claiming they had come up with no alternative to the accord.
A standing ovation greeted his speech to the Ulster Unionist Council in Belfast on Saturday, but just before the annual meeting ended a number of people heckled Mr Trimble, demanding no fudge on disarmament.
Mr Trimble appeared taken aback when asked from the floor if there would be any compromise on IRA decommissioning. As he began to speak about "credible" disarmament another speaker demanded an assurance he would "pull the plug" on the agreement if decommissioning was only partial.
The party president, Mr Josias Cunningham, then called for the singing of the anthem, which in turn prompted a few cries of "shame, shame", and "answer the question!".
About 600 delegates from the 800-member council, the UUP's governing body, returned Mr Trimble unopposed as party leader. Pro-agreement unionists also held the line in the election for the four posts of party vice-presidents. Returned were Trimble loyalists Mr Ken Maginnis, Sir Reg Empey and the UUP MEP Mr Jim Nicholson.
The Rev Martin Smyth MP, a patron of the dissident Union First group, was also returned, topping the poll to take a vice-presidency. Mr William Ross, MP, also a dissident, failed by just 16 votes to take the fourth position.
There was further tension when two Trimble supporters, Mr Dermot Nesbitt and Mr Dennis Rogan, failed to dislodge any of the four sitting honorary secretaries, three of whom are Union First supporters - Mr Jeffrey Donaldson, Mr David Brewster, and Ms Arlene Foster. Mr Peter Weir, a member of the Assembly and Union First, said the voting proved that his organisation had prevented the creation of a "party of pro-agreement sheep".
Mr Trimble was scathing of anti-agreement unionists, claiming that the divisions within unionism had shredded the unionist vote and allowed nationalists to gain political ground.
"At no stage have the anti-agreement parties - four of them now! - done anything to help. Worse, their division has robbed unionism of a sixth ministerial position on the executive."
Of the DUP Mr Trimble stated: "They are not really interested in succeeding with their policies. Their real interest is in striking postures, in scoring points. They care more about that than on whether unionism is winning or losing. We, on the other hand, focused on the big picture, on the long-term interests of unionism and on building a better future."
Mr Trimble repeated his demand for IRA decommissioning before Sinn Fein took up its two positions in the executive. "We are ready for the transfer of power to the Assembly. We look forward to proceeding on an inclusive basis - a basis where through the broad executive or the comprehensive committee structure all elements in the Assembly can work together on this great project," said Mr Trimble.
"All the work needed to be done to enable the institutions to go live has been done. But on one issue there has been no progress, the commitment that all parties to the agreement gave to `the total disarmament of all paramilitary organisations'."
He said that disarmament was necessary because it implied a real commitment to peace. "But if dealing with the weapons is a problem then that implies that there is not a genuine commitment to the agreement. And if there is no real commitment then we all have a problem. It is time for the problem to be resolved.
"As Bertie Ahern said, in the referendum we did not vote for an armed peace. There is no alternative to the agreement. None of the Nos, whether republican dissident or Union Firsters, has produced one. And society throughout the British Isles does not want and will not tolerate a return to violence.
"So, it is not a question of whether, but when. For us the sooner the better. Then, after the credible beginning of decommissioning we can all begin to leave the Troubles behind. It is time to focus on the future."
Mr Trimble said the "wounds and divisions" within unionism must end. "Real unionist unity must start here in this party."
"Running the new administration will be difficult enough without self-inflicted wounds.
"The agreement is a long-term investment in the future that has the potential to transform the face of society in Northern Ireland. It secured unionism's constitutional objectives. It guaranteed the union through the principle of consent. An equitable and fair administration with nationalist participation will strengthen our future within the union.
"It replaces the Anglo-Irish Agreement, abolishes the territorial claim and brings cross-Border co-operation under the aegis of the Stormont Assembly.
"Unionism in the past 12 months has gained more international respect and recognition than it has in the past 30 years. We have countered republican propaganda despite all its resources and networks. We did it because we have the better case."
Mr Trimble said there were some parts of the agreement which were difficult for unionists. "But they are mainly short-term. As we enter the new millennium those with misgivings will see the future under the agreement is much better than the last 27 years under direct rule. The time has come to take control of our future. We must not let it go.
"Monsignor Denis Faul on [the BBC programme] Talkback on Tuesday, in the aftermath of the appalling murder of Rosemary Nelson, said that the killing reinforced the need for an end to all violence. He said: `I believe the majority of people in the Catholic community have moved on. They believe now in the alternative to violence, which is education, hard work and respect for the rights of others.' "
Mr Trimble concluded: "I agree. It is time to move on. It is time for all of us to move on. I believe the Ulster Unionist Party is ready. I believe the greater number of people are ready, ready for the hard work of building a Northern Ireland of which we can all be proud."
