There have been conflicting reactions from the North's First Minister, Mr David Trimble, and a senior Sinn Fein spokesman to a call for IRA decommissioning made by the British Prime Minister yesterday.
Mr Blair's remarks came in response to a House of Commons question from Mr Trimble, who pointed out that the Taoiseach, Mr Ahern, recently indicated in a newspaper interview that IRA decommissioning should take place before Sinn Fein could take its seats on the new Northern executive. The UUP leader asked the Prime Minister what his advice would be to the republican movement.
Mr Blair replied: "The advice is very clear, that they should decommission their weapons - we've always said that, I say it again now. I agree with what the Taoiseach said. The whole of the agreement must be implemented and we must know that violence has been given up for good, as we've always said and it's unreasonable to expect people to sit down together unless they know that that is the case."
Shortly afterwards Mr Trimble said in a statement that he welcomed "the Prime Minister's agreement with the Irish Prime Minister's statement - that IRA decommissioning must start before Sinn Fein can take seats in the Northern Ireland executive".
He said it was "unreasonable to expect people to sit down together" in the executive unless the process of disarmament has begun.
"The moment of truth is now arriving for the republican movement. Public opinion across the British Isles and beyond is crystal clear on this issue. You cannot have an armed peace. The issue of illegal terrorist weapons has to be faced now."
Also responding to Mr Blair's comments, the Sinn Fein chairman, Mr Mitchel McLaughlin said: "No one should be giving succour or encouragement to those opposed to the peace process."
He said Sinn Fein's right to positions on an executive was "based solely on its democratic mandate received in successive elections". The decommissioning problem could be resolved under the mechanisms provided by the Belfast Agreement.
Meanwhile, the Ulster Unionist Party and Sinn Fein delegations' meeting last week has been followed by further contact at senior level and more discussions are envisaged next week.
However, suggestions in newspaper reports that the UUP might allow "wriggle room" to republicans on the timing of decommissioning have been described as "quite astonishing" by the party's MP for East Londonderry, Mr William Ross.
"The proposal now floated, like the earlier concept of allowing General de Chastelain to be the arbiter as to whether disarmament had taken place, is quite unacceptable to the unionist population who expect the manifesto position of the UUP to be delivered in full on this vital issue.
"Indeed, saying that the UUP is flexible on decommissioning can only encourage the IRA to believe that they can hold on to their weapons and still have their political mouthpieces in the executive," Mr Ross said in a statement.
Republican sources were adamant yesterday there would be no decommissioning of any kind by the IRA to secure Sinn Fein participation in an executive and they also categorically dismissed suggestions that the IRA was actively preparing to end its ceasefire.
Meanwhile, speaking in the Commons, the SDLP chief whip, Mr Eddie McGrady, said even a "gesture" on decommissioning would unlock the blockages delaying full implementation of the Belfast Agreement.
The Northern Secretary, Dr Mo Mowlam, said: "What needs to happen is the parties in the process that signed up to the Good Friday agreement do what they are doing in Belfast now, which is keep talking and find a way forward."
Efforts were continuing to resolve the Drumcree stand-off, she said, and Mr Frank Blair, head of the Scotland branch of government conciliation and arbitration agency, ACAS, had been asked to "to do what he can to act as a negotiator and someone to help out that process". The North's Security Minister, Mr Adam Ingram, called on critics of the Royal Ulster Constabulary to "move away from empty rhetoric and accept the democratic process". He added: "There can be no justification for bullying, intimidation and harassment or for brutal summary justice on the pretext that the RUC is an unacceptable police force."
Mr Ingram said it was not appropriate to guess the Patten Commission's recommendation. "But the two extremes of no change and the total disbandment of the RUC are not likely to be on the Commission's - and they aren't on the government's - agenda."
Ms Bairbre de Brun of Sinn Fein said in a statement on the RUC: "The British government should be assisting the disbandment of the force and encouraging the development of a policing service acceptable to the entire community, rather than tinkering at the edges of the RUC."