Both men said it had been a positive meeting, with Mr Trimble describing it as "workman like" and Mr Adams describing it as "useful".

Relations between the two party leaders are known to be cool.

They discussed the ongoing problems in the political process and the recent initiative by loyalist paramilitaries to begin a "no first-strike policy".

We need to see rapid progress towards a situation where everybody is demonstrably operating only by exclusively peaceful means

David Trimble Ulster Unionist leader

Mr Trimble said: "There is a very obvious crisis of confidence... there is an extremely delicate situation, politically and in terms of the situation in Belfast."

He added: "We need to see rapid progress towards a situation where everybody is demonstrably operating only by exclusively peaceful and democratic means.

"That means facing up to the existence of paramilitary organisations and the need for them to change."

Mr Adams said everyone had a responsibility to bring a calming influence to end violence.

"It is very, very important that we set an example and make it very clear that there is only the Good Friday Agreement and that there is no alternative," he said.

"I don't think any sense of governments or anyone else bringing sanctions against any party is the way to go forward."

The Sinn Fein leader said the pro-Agreement parties should come together for a "stock-taking exercise" of progress since the signing of the Agreement.

"The big pressing issue is to ensure that people who are facing July with some considerable anxiety need to have some sense of confidence that this is going to be a calm July - that this month isn't going to end as it began."

Revelations

Earlier on Monday, Secretary of State John Reid said he was not considering suspending the Northern Ireland Assembly at the moment.

He was responding to unionist pressure for sanctions against republicans over recent alleged IRA activity in Colombia.

At the weekend, Mr Trimble said he would consider resigning again as first minister to make progress with the Good Friday Agreement.

Some members of his party have been calling for a withdrawal from the power-sharing executive if the British Government does not move to exclude Sinn Fein from the executive.

It followed revelations on Thursday that security sources believe the IRA had been testing new weapons in Colombia.

We understand that there is a confidence in the peace process which needs to be injected

John Reid

Meanwhile, Deputy First Minister Mark Durkan has met Prime Minister Tony Blair and Dr Reid at Downing Street.

Dr Reid said he hoped to gather the parties together to discuss the current situation.

"I would not want to use the word danger but I think there are concerns about the process in general," he said.

Mr Durkan said he was not aware of the terms of any forthcoming meeting of the parties, but pointed to a meeting of the implementation group next week.

"What we have to do is consolidate the Agreement and not threaten those parts of the agreement that are already there and working," he said.

UK Prime Minister Tony Blair and Irish counterpart Bertie Ahern have agreed to convene crisis talks of the pro-Agreement parties within the next few days.

It is understood talks will concentrate on trying to resolve the current difficulties in the process and questions raised about the ambiguities of the present paramilitary ceasefires.

Dr Reid played down these difficulties, but accepted that confidence was low.

John Reid: confidence injection needed

"We understand that there is a confidence in the peace process which needs to be injected," he said.

"When we embarked on this I think there was a great euphoria.

"Everyone believed it would be relatively easy and what people have recognised since then is that it needs constant application...and that is why we decided to bring the parties together at this stage to try to put some momentum into the process."

Sinn Fein's Mitchel McLaughlin predicted the forthcoming talks involving the pro-Agreement parties would be a "slanging match".

However, the Foyle MLA said he was upbeat about the prospects for agreement and that there was common ground amongst all the parties.

"We anticipate - and it is not a question of if but when - we will sit down with the representatives of the Democratic Unionist Party as well," he said.