But Mr Adams warned that success would depend on the parties and governments involved in the process maintaining a "cautious and measured approach".

He said the limits to which his party and its constituency had been stretched by the latest developments should not be underestimated by the British establishment and wider Unionist family.

He appealed directly to the British government to resist the temptation to over-hype the progress made since the beginning of the week and urged it to adopt an approach which was "sure-footed" and "calm".

"Everyone in leadership needs to be mindful that peace-making is more important, is different from, more difficult than conventional politics or what usually passes for conventional politics.

"It means trying to put yourself in the shoes of your opponents, it means resisting the temptation to go for short term advantage, it involves resisting the urge to misrepresent, hype or to exaggerate," he said.

"As much as anything else, the success of the next phase may depend on everyone taking a measured and accurate approach in the period ahead."

Ulster Unionist negotiator Michael McGimpsey said the IRA statement could convince his party that republicans are serious about decommissioning.

'Enhances prospect of peace'

Mr McGimpsey said the way could now be open for the formation of an executive.

"There is a possibility that we could be in business.

"Business for us is achieving our party's twin objectives of decommissioning and devolution - crudely put 'no guns, no government'."

Irish Taoiseach, Bertie Ahern: "IRA statement is a positive development"

Irish prime minister Bertie Ahern described the statement as a positive development when taken in tandem with Tuesday's declaration by Sinn Fein.

He said the previous IRA statement was seen as a less than positive endorsement of the agreement arrived at Hillsborough in April and a lack of a statement July was a setback.

The IRA statement was also welcomed by Social Democratic and Labour Party (SDLP) leader John Hume who said it marked a "further advance towards the establishment of all the political institutions of the agreement and the process of decommissioning."

"The significance of this step should not be underestimated and it is essential that the momentum created by the events and statements made this week is continued."

Earlier, the Ulster Unionist leader David Trimble had been warned not to try to sell his party a deal on offer from republicans by senior party colleagues.

The warning came from dissident party officer Arlene Foster who said a deal would "split the party irrevocably".

Ms Foster, an honorary secretary with the party, said she has serious concerns about its future if the deal is accepted.

She claimed many unionists were "in the dark" about what was happening.

"I think if he (Mr Trimble) tries to sell this to the party, it will be split and it will be the end of the Ulster Unionist Party as we know it today."

A similar call was issued on Tuesday by Lagan Valley MP Jeffrey Donaldson.

Sir Reg Empey: Party is "doing something"

However, a senior member Ulster Unionist Party (UUP) talks team has defended Mr Trimble saying tough decisions are needed in order to achieve progress.

Sir Reg Empey said: "Any party that's trying to achieve its policy objectives and having to take tough decisions, always runs the risk of having divisions.

"But I would rather be in a party that's trying to do something instead of some people that are sitting on the sidelines and doing absolutely nothing."

It is likely that any deal would be debated at the next meeting of the 800-strong Ulster Unionist Council, the party's governing body.