Tony Blair and Bertie Ahern have been holding key talks to end the deadlock in the Northern Ireland peace process.

The two leaders were among a series of senior ministers and politicians attending an Anglo-Irish summit in Downing Street.

Also attending the meeting were Ulster Unionist leader David Trimble and Sinn Fein president Gerry Adams.

It is hoped the summit will help to produce an agreement on fresh elections to the Stormont assembly.

The government faces a Wednesday deadline for setting a new date for the elections, which were postponed earlier this year following the collapse of the power sharing executive.

Speaking after the morning session of talks concluded, the prime minister offered an upbeat assessment.

"The omens are all very, very good if we can find the right way of having the election in a positive and constructive atmosphere, and I hope very much that we can do that," Blair said.

And after the talks concluded, Adams said that all parties should seek to make progress together.

"The only way I think that we can make the type of progress that is required is if we collectively proceed," he said.

Earlier, Number 10 sought to play down the significance of the meeting with a warning that there would be "no decisions", but admitted that "everyone is aware that time is short".

"The building blocks are there for a deal which will allow us to go into the elections in a positive state of mind but the work is still not yet done," said an official spokesman.

"We have seen the quietest summer for over 30 years. We have also seen the most intensive period of negotiations between the parties since the agreement itself."

Number 10 also signalled that the government was prepared to risk missing key deadlines if a deal could be reached.

"Northern Ireland deadlines tend to be a bit flexible in their interpretation. Let's see where we get to," said the spokesman.

Unionists want assurances from Sinn Fein that the IRA will prove it is committed to giving up weapons for good before returning to government alongside republicans.

Ahead of the talks, Trimble said that people in Northern Ireland want to see the assembly restored.

"The question is whether the assembly can be a functioning one," he added.

"Whether we can [succeed] depends on whether republicans can meet the challenge this time as they failed to do in April."

And Ahern conceded that all sides were "not making the progress Tony Blair and I had hoped to make".

"The positive is that the parties [in Northern Ireland] are very much committed to engaging. They have worked very hard to try to make progress," he said.

Ongoing dialogue between the opposing sides was "very important because it is they who must work together in any functioning executive after the election", Ahern added.

"Naturally, I welcome the engagement between Sinn Fein and the UUP, and I understand it is continuing," he said. "That is to be encouraging in itself."

"We want the elections to be held in a positive, pro-agreement atmosphere - that is in the best interests of the peace process generally, and of the pro-agreement parties."