The British Government is "working hard to find a way to try and disclose" the details of IRA decommissioning which stalled the political process, Tony Blair has said.
The PM said people would be satisfied if they knew the details
Speaking in the Commons, the prime minister said he was trying to resolve
what he described as an unsatisfactory situation.
Hours later, senior members of Sinn Fein and the Ulster Unionists met in an effort to sort out their differences over decommissioning.
Sinn Fein's Martin McGuinness and Michael McGimpsey of the UUP held talks on Wednesday evening.
On Tuesday, Ulster Unionists rejected the IRA's latest act of decommissioning as not being transparent enough.
Talks resumed on Wednesday in an effort to rescue a potential deal to restore devolution in Northern Ireland.
Arms chief General John de Chastelain's report confirmed the quantity of weapons put beyond use by the IRA was "considerably larger" than that which had been previously decommissioned by the republican movement.
Mr Blair told MPs: "Under the decommissioning legislation, it is open to a paramilitary organisation to decommission with confidentiality. That is the arrangement they entered into with General de Chastelain."
He added: "We are not at liberty to disclose that information, but we are
working hard to find a way to try and disclose it.
"On the basis of what we know, people would be satisfied if they knew the
"Unionists need to be sure that what is being said is a substantial act of
decommissioning is indeed a substantial act of decommissioning."
Ulster Unionist peer Lord Rogan has called on the government to explain how legislation prevents the disclosure of information on the IRA's latest act of decommissioning.
Speaking in the Lords on Thursday, he asked to who the confidentiality clause applied.
"If, as the prime minister suggested, the IRA has undertaken a substantial act of decommissioning and is now finally and fully committed to the political process, will the government now assist in rebuilding lost confidence by disclosing the details of the latest decommissioning event?" he asked.
Speaking in the Irish parliament on Wednesday, Irish Prime Minister Bertie Ahern said he knew a lack of detail over IRA decommissioning would prove problematic for the political process.
He said a demand for clarity was always going to prove a difficulty.
Mr Ahern told the Dail that Downing Street was aware that on Tuesday morning he was reluctant to travel to Hillsborough because of concerns about the decommissioning element.
Northern Ireland Secretary Paul Murphy later told the Commons he had made an order to enable fresh elections to the assembly to take place on 26 November.
Speaking earlier on Wednesday, Ulster Unionist leader David Trimble said he had made it clear to republicans "what would be successful and what would not be successful".
"When we listened to de Chastelain and realised they had imposed restrictions on him, and had not given the information that they knew was necessary, then we knew there was a serious problem," he said.
"That's why I put things on hold."
Speaking at a news conference on Wednesday, Sinn Fein President Gerry Adams said there had been an agreement reached and all parties to the "sequencing" of Tuesday knew what was to take place and there were now profound difficulties.
"If this is to be sorted out in the short term and the short term... clearly means within the next few days, because obviously if it is not sorted out in the next few days, then it will have to be put off until after the election because there is really no other way of dealing with it," he said.
It was of key importance that when a commission established under law said it had witnessed IRA decommissioning in accordance with a government scheme, it was up to the two governments to "defend it, promote, validate and uphold it", said Mr Adams.
"Following our discussions and even our attempts to have dialogue this morning, we still have no satisfactory explanation why the agreed sequences did not go forward," he said.
At a news conference on Wednesday, DUP leader Ian Paisley denounced Mr Trimble and the prime minister.
"This election is the opportunity to deliver a verdict on what Trimble and the Official Unionists have done over the past five years," he said.
"They signed up to a deal, which has delivered concessions to the IRA, not just on one day in 1998, but for every day since."
A delegation from the DUP is meeting General de Chastelain on Thursday.
The devolved administration at Stormont was suspended a year ago amid allegations of IRA intelligence-gathering in the Stormont government.
The announcement of an election date came after weeks of top-level negotiations between Sinn Fein and the Ulster Unionists, as well as the British and Irish Governments.
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