Ulster Unionist Assembly member Mr Michael McGimpsey has said that while Gerry Adams's statement contained some promising elements, there had to be actual movement from the Provisional IRA on decommissioning.
Mr McGimpsey, a leading pro-agreement unionist, said: "So far these are words and we have been at pains to state that words are not enough - we want to see action.
"However it would be begrudging of me not to state that there are promising parts in this statement that may be heralding further steps. At this point in time nothing has actually happened in terms of actions. What we have here is the appearance of a promise. We must wait to see further developments."
Anti-agreement Assembly member Mr Peter Weir dismissed Mr Adams's statement as a cynical ploy.
The Provisional IRA was under increasing international pressure and in an attempt to "get off the hook" was preparing to make a one-off gesture on decommissioning. Unionists could not believe in the sincerity of Sinn FΘin, he said.
"We are asked to trust a party which, after weeks of denial, has just admitted that one of the Colombian Three was there on Sinn FΘin business. Why then should we believe that the single gesture that is bound to come in the days ahead will show any intention of long-term commitment to peace and democracy?"
DUP leader the Rev Ian Paisley also dismissed Mr Adams's statement. It was nonsense for him and Mr Martin McGuinness to say they had been meeting the Provisional IRA on the arms issue, Dr Paisley said.
"All they have to do is look in the mirror every morning when they are shaving." Mr Adams had not expressed regret for Provisional IRA actions in his statement, and the DUP leader was not prepared to trust him: "Gerry Adams lies through his teeth and I am not prepared to trust a liar."
He said he believed a deal had already been struck between Sinn FΘin, Mr Trimble, and the two governments and he predicted there would soon be a statement from Gen de Chastelain's decommissioning body on Provisional IRA weapons.
Mr David Ervine of the Progressive Unionist Party, the UVF's political wing, urged the Provisional IRA to now state its war was over.
"Everything the IRA has done up to now has been begrudging, so let us see what the style and nature of this (decommissioning) is," he said.
There was no evidence loyalists would make a reciprocal gesture, he said, but he added: "If there are positive moves by republicans to save the process then maybe people can think about what they can do to assist the process."
Patrick Smyth, Washington Correspondent, adds: The US government last night welcomed the comments of the Sinn FΘin leader and urged politicians to respond to decommissioning if it happens "with generosity and vision".
The deputy spokesman of the State Department, Mr Philip Reeker, said: "We believe that Gerry Adams's speech today constitutes a significant statement. We very much hope the Irish Republican Army decides to take the historic step of placing arms beyond use. We agree wholeheartedy with his words that a ground-breaking move by the Irish Republican Army on the arms issue would breathe new life into the peace process."