Sinn Féin has accused the DUP of refusing to move on any of the substantive issues at the heart of Stormont's power-sharing talks.
The talks were adjourned shortly after 10.30pm, with discussions due to resume tomorrow morning.
SF party chairman Declan Kearney did hint movement was possible on one precondition, its opposition to DUP leader Arlene Foster returning as Stormont first minister, if the DUP gave ground on other matters.
Mr Kearney claimed the DUP was not prepared to move on demands for a stand-alone Irish Language Act, the introduction of same sex marriage in Northern Ireland and the introduction of a specific bill of rights for the North.
His comments came after Northern Ireland Secretary James Brokenshire warned that time was running short to strike a deal.
The parties have until 4pm on Thursday to restore a devolved executive or Northern Ireland faces the prospect of a return of direct rule from London.
On dedicated Irish language act DUP’s Edwin Poots says there can't be a position where one culture is recognised over & above other cultures pic.twitter.com/gvh4oO4bxF— RTÉ News (@rtenews) June 27, 2017
Irish language act a sticking point in NI power-sharing talks pic.twitter.com/cs0HUulVyU— RTÉ News (@rtenews) June 27, 2017
Mr Kearney said: "The DUP have not moved on any of the substantive issue which sit at the heart of this crisis.
"They haven't moved on any of the fundamental rights and equality issues that require to be embraced."
Asked if Sinn Féin was prepared to drop its opposition to Mrs Foster returning as first minister while a public inquiry into a botched green energy scheme is ongoing, Mr Kearney again stressed the urgent need was to address the "rights and equality" issues.
But he added: "In those circumstances if in fact we can find resolution and progress on all of the fundamental issues then we can address the issue of the future role of the DUP leader in a possible future executive but at this point that question is academic."
DUP negotiator Edwin Poots urged Sinn Féin not to engage in "high wire acts".
He suggested a "parallel process" could be initiated where an executive is formed while talks on the outstanding issues continued.
Mr Poots said negotiations were ongoing.
"I can't say they are easy but nonetheless we want to get Stormont up and running and we can get it up and running straight away and distribute the money our DUP have successfully received from the UK government," he said.
"We believe we need to be respectful of all cultures and all traditions across Northern Ireland and are working hard to find a means through that and ensure that we can continue to deliver.
"I would encourage Sinn Féin to be mature, no high wire acts, let's get down to work, knuckle down and find a way through this and it is possible if people apply themselves."
Mr Brokenshire claimed intensive engagement was continuing inside Stormont Castle, with the parties focusing on differences over equality and language issues.
"Time is marching on," he said.
"It is about now reaching that conclusion, meeting that statutory deadline of Thursday afternoon and finding a way through in the best interests of Northern Ireland."
While negotiations involve the five main Northern Ireland parties and the Irish and British governments, their fate hinges on whether the DUP and Sinn Féin can resolve their differences.
Mr Brokenshire has stressed the cut-off point was set in law, he did not definitively rule out another extension.
"It was an act of parliament that set that and therefore it is that very clear deadline that we are seeking to ensure is met," he said.
Mrs Foster was forced from office in January when Sinn Féin's then deputy first minister, the late Martin McGuinness, quit in protest at the DUP's handling of the ill-fated renewable heat incentive scheme.
His move triggered a snap Assembly election in March.
A number of attempts to restore power-sharing in the wake of that poll floundered, with three UK government deadlines for a deal having already been missed.
Civil servants have been running Stormont departments since March.
A form of direct rule from London is likely to be reimposed in lieu of a deal.
It remains unclear what impact the DUP's Westminster parliamentary deal with the Conservative Party will have on efforts to restore power-sharing.
While rival Stormont parties have largely welcomed the additional £1 billion investment flowing from the confidence and supply agreement, concerns have been raised as to whether the UK government has fatally compromised its stated commitment to impartiality in its dealings with Northern Ireland parties.
British PM tells Varadkar Britain remains committed to GFA
British Prime Minister Theresa May has told Taoiseach Leo Varadkar the deal with the DUP "makes clear" that Britain remains committed to the Good Friday Agreement and to governing in the interests of "all parts" of the community in Northern Ireland.
After they spoke on the phone, a Downing Street spokeswoman said: "The Prime Minister explained that the DUP will support the Conservative government on votes on the Queen's Speech, the Budget, and legislation relating to Brexit and national security.
"The Prime Minister went on to say that the agreement makes clear that the United Kingdom remains steadfast to our commitments as set out in the Belfast Agreement and its successors, and in governing in the interests of all parts of the community in Northern Ireland.
"They confirmed their joint commitment to restore a Northern Ireland Executive as soon as possible and agreed to engage closely, and work with the parties in Northern Ireland, to bring back political stability and a strong voice at Stormont."