The Ulster Unionist leader, Mr David Trimble, has claimed his political strategy has been vindicated by the Provisional IRA decommissioning a substantial quantity of weapons.
He described the act as "highly significant" and said it made many anti-Agreement unionists, including those within his own party, look foolish.
However, leading anti-agreement figures dismissed the decommissioning as a propaganda stunt to improve Sinn Féin's chances in the forthcoming general election.
"Those who said there would never be any decommissioning were proved wrong last October," Mr Trimble said. "Those who said it was a one-off gesture, and that hope of a process was just wild optimism, have now been proved wrong."
He regretted the IRA had not made public the precise nature of what it had decommissioned and he called on loyalist paramilitaries to begin decommissioning.
Anti-Agreement UUP MP, Mr Jeffrey Donaldson, said the latest act had "more to do with the Irish general election and deflecting attention from the Castlereagh break-in than it has to do with commitment to peace and democracy".
Another anti-agreement UUP MP, Mr David Burnside, said: "I find the whole thing totally hypocritical when it appears the Provisional IRA have been up to their necks in the Castlereagh break-in. This is a PR exercise for consumption in the Irish Republic for the forthcoming elections. It is propaganda by day and a continuation of terrorism by night."
The DUP deputy leader, Mr Peter Robinson, said the decommissioning meant nothing. "It is an event of no significance. It will not impress anybody from the unionist community, which is still waiting to find out whether it was one or two guns decommissioned the first time."
The Northern Secretary, Dr John Reid, said it was particularly encouraging that the decommissioning body had described the arms put beyond use as "varied and substantial".
Loyalist paramilitaries must "match the IRA's important action with steps of their own," he said.
The SDLP leader, Mr Mark Durkan, criticised those who claimed the decommissioning act was geared solely to the approaching election. "We want to see progress in relation to loyalist decommissioning. It would assist and boost public confidence," he added.
The Republican Sinn Féin president, Mr Ruairí Ó Brádaigh, said the IRA had no right to decommission weapons bought "for the freedom of Ireland".
He added: "In time, those who so collaborate with the British forces of occupation will be reviled by their people as are the quislings and traitors of World War II."
The Women's Coalition welcomed the latest move as showing "decommissioning is a process and not a one-off act - a verb and not a noun".