NI talks: Political parties continue discussions
Further discussions are taking place among Northern Ireland's political parties on Tuesday.
The talks are aimed at resolving outstanding disputes over flags, parades, the legacy of the Troubles and welfare reform.
The discussions come after a financial package for the Northern Ireland Executive was rejected by Stormont.
Talks involving the British and Irish governments and the parties will formally recommence on Wednesday.
Speaking on Tuesday, Sinn Féin leader Gerry Adams said that he did not know if there would be a deal by Christmas.
He said that a comprehensive agreement was still possible and that there was no willingness of anybody in the executive to collapse the institutions.
"If the institution is under any threat at this time it is because of the posturing of Mr Cameron and the taoiseach [Enda Kenny]," he said.
"If we knuckle down there's no reason why there cannot be a deal done."
Justice Minister David Ford said the sustainability of the Northern Ireland Assembly was open to question.
David Cameron flew to Belfast last Thursday for all-party talks but left on Friday morning without a deal.
On Monday, two former Northern Ireland secretaries of state expressed concern about the prime minister's handling of last week's political talks in Belfast.
Peter Hain told the House of Commons he was astonished that Mr Cameron had left the talks as soon as he did.
Paul Murphy advised the current Secretary of State, Theresa Villiers, to persuade Mr Cameron to return to Northern Ireland quickly.
She defended the prime minister and said he had not walked away.
She said Mr Cameron followed the process with the greatest attention because he cares about Northern Ireland and wants to see a successful conclusion.
Ms Villiers said the prime minister and his Irish counterpart, Enda Kenny, had made an assessment there was no chance of a deal on Friday, because some of the parties were not prepared to move on key issues and that, in particular, Sinn Féin would not move on welfare reform.
This week has been billed by the Northern Ireland Secretary as a crunch time for cross-party talks in Belfast and she said she believes a pre-Christmas deal is crucial.
She is concerned that unless a deal is agreed this week, the House of Commons will run out of parliamentary time to give the Northern Ireland Executive corporation tax powers before the 2015 general election.