THERE were fears talks to restore power-sharing have collapsed after discussions ended abruptly on Friday night.
The talks stopped at around 7.30pm with no sign of a breakthrough in major sticking points including an Irish language act.
It is understood senior Sinn Féin members have questioned the DUP's commitment to the process.
While the talks are expected to resume on Saturday morning, they may be brief.
British Prime Minister Theresa May telephoned DUP leader Arlene Foster and Sinn Féin's leader in the north, Michelle O'Neill, on Friday evening.
A No 10 spokeswoman said Mrs May told Mrs Foster "it was encouraging to see discussions continuing and it was important that momentum is maintained so an Executive can be restored and they both agreed that this was in the interest of everyone in Northern Ireland".
She made similar comments to Ms O'Neill and urged the parties to "come together reach a collective agreement".
Sinn Féin MLA Gerry Kelly said his party's negotiators would return to Stormont Castle today.
"After weeks of negotiations there is still no agreement by the DUP on the issues, of Acht na Gaeilge, the Bill of Rights, marriage equality, anti-sectarian measures, integrity and legacy, which collapsed the Assembly in January," he said.
Earlier, both parties continued to blame each other for the impasse.
Sinn Féin's Conor Murphy accused the unionist party of "burying their head in the sand" after the DUP's Edwin Poots claimed the republicans' stance was impacting on the delivery of public services.
Mr Murphy said: "I have to say the DUP are in absolutely no position to lecture anyone in relation to the provision of public services when they have taken a decision to keep in power a government which has taken more than a billion pounds off our ability to finance public sector services".
Earlier, Mr Poots ridiculed Sinn Féin's call for Mrs May and Taoiseach Leo Varadkar to intervene in the crisis talks as a "matter of urgency", insisting the republicans "don't need anyone to hold their hands".
No 10 said Mrs May had been in touch with the parties but Secretary of State James Brokenshire was the UK government's representative.
Following further negotiations at Stormont Castle yesterday - after Thursday's deadline for agreement was missed - Mr Poots said: "I think Sinn Féin can do the business very quickly, they know what's required of them - they don't need anybody to hold their hands".
"They just need to sit upstairs, make the decisions that need to be made and come and tell us of those decisions so we can get on with the business," he said.
Accusing the DUP of refusing to budge on central issues, Sinn Féin negotiator John O'Dowd earlier urged the two governments to press the main unionist party to give ground.
Mr O'Dowd claimed the DUP had become "emboldened" by its parliamentary deal with the Tories at Westminster and had entrenched its stance at Stormont as a result.
He said any progress had been very slow and said the main sticking points related to his party's demands for an Irish language act, a Bill of Rights and legalisation of same sex-marriage.
"We will stay here as long as there is a glimmer of hope that there will be success in these talks, but we are realists and we are experienced negotiators and we know there needs to be a step change in these talks - hence the reason we are calling on the Taoiseach and the British Prime Minister to become directly involved," he said.
Mr Poots said his party wanted Sinn Féin to compromise on issues including the military covenant and "confidence building" proposals to reform the Stormont institutions.
He told Sinn Féin to "get moving so we can get government back in place".
Mr Brokenshire is due to make a statement to the House of Commons on Monday.
In the absence of any agreement, he can set another deadline for the talks process, call a second snap Assembly election or re-impose direct rule.
