Sinn Féin and the Democratic Unionists are hammering out details of a potential deal that could end Stormont's 13 month powersharing crisis.
The North's two main parties were locked in negotiations through today, scrubbing a scheduled round table meeting with the region's smaller parties, amid mounting speculation an agreement may be in sight.
This evening, Sinn Féin acknowledged progress had been made toward a breakthrough but insisted issues remained. The republican party said the talks process should conclude next week.
Party president Gerry Adams, who will step down from his leadership role tomorrow, said: "It isn't sorted out as we speak. We have made some progress but there are still considerable obstacles but as I said to our unionist friends, this is the last chance agreement.
"They need to embrace the need for rights for everybody and agree a space where we can all moderate our differences."
Stormont's five main parties had been due to meet for round table discussions with Northern Ireland Secretary Karen Bradley and Tánaiste Simon Coveney at Parliament Buildings in Belfast this afternoon.
The DUP and Sinn Féin did not attend, with Mrs Bradley telling the other participants the meeting would not proceed as planned because the main parties were involved in intense exchanges elsewhere in the building.
The episode has fuelled expectation of a possible breakthrough.
Earlier: Sinn Féin and DUP continue powersharing talks without smaller parties
Sinn Féin and the Democratic Unionists remained locked in negotiations to salvage powersharing on Friday evening after a scheduled all-party meeting was scrapped at short notice.
Stormont's three smaller parties - the Ulster Unionists, SDLP and Alliance - attended the afternoon talks session in Parliament Buildings and were told by the UK and Irish governments it would not proceed as planned because the DUP and Sinn Féin leaderships were involved in intense exchanges elsewhere in the building.
The episode has fuelled already mounting speculation that the two largest parties have made progress in their efforts to strike a deal that would end the impasse that has left the North without a properly functioning devolved executive for more than a year.
The last DUP/Sinn Féin-led coalition imploded last January amid a row over a botched green energy scheme.
That rift subsequently widened to take in long-running disputes over culture, social issues and legacy.
The main sticking point preventing the restoration of an executive is the Irish language. Sinn Féin want a stand-alone piece of legislation to protect speakers - an Irish Language Act - but the DUP has long insisted it would only countenance new laws if they also incorporate other cultures, such as Ulster Scots.
Tánaiste Simon Coveney and Secretary of State Karen Bradley spoke with the three smaller parties at the truncated meeting on Friday afternoon.
According to sources, Mrs Bradley said she understood they were frustrated with the turn of events, to which UUP leader Robin Swann apparently replied he was not there for a "counselling session".
SDLP leader Colum Eastwood is understood to have told Mrs Bradley she had his number and to give him a call when she intended on having "inclusive" talks.
A UUP source said: "Sinn Féin and the DUP are clearly running these talks and the two governments are just bystanders".
Substantive negotiations between the two main parties are unlikely to continue through the weekend as Sinn Féin is holding a special party conference in Dublin on Saturday to formally select Mary Lou McDonald as Gerry Adams' successor as president.
The DUP is also traditionally averse to doing business on Sunday.
Later, Mr Eastwood said it was clear the negotiations were an "exclusive two-party process".
"The SDLP are not here to window dress but we want to be constructive," he said.
"I've told both governments when the two-party process is concluded and they are ready to engage in five-party negotiations, the SDLP will be ready to negotiate.
"With a hard Brexit coming down the tracks that will cause economic, social and political chaos to our island, I also stressed to the Irish and British governments the need for the formation of a government urgently. Everyone across these islands is talking about the threat of a hard border, yet here we have a political vacuum."