It is decision time for political leaders pondering a return to powersharing in Northern Ireland, a senior Ulster Unionist said.
The two largest parties, Sinn Fein and the DUP, continued dialogue late into the evening on Wednesday and fresh negotiations were held on Thursday.
Three years since the late deputy first minister Martin McGuinness resigned and triggered the collapse of the devolved institutions at Stormont, endless rounds of talks have failed to engineer their resurrection.
Former Ulster Unionist leader Mike Nesbitt said the deadline was Monday and the Northern Ireland Secretary chairing proceedings needed to do no more than ask the parties was it a yes or a no.
He added: "Negotiations should be over, it is decision time."
Powersharing collapsed in a row over a botched green energy scheme.
Divisions between the DUP and Sinn Fein over the creation of an Irish language act have prevented its restoration.
Mr Nesbitt said: "We need the DUP and Sinn Fein to show leadership by making a decision today."
A DUP source downplayed the prospect of a breakthrough on Thursday.
He added: "The parties have a lot of work to get through."
DUP MPs were travelling back from London on Thursday for an anticipated meeting with party colleagues on the state of the negotiations.
Sinn Fein vice-president Michelle O'Neill said her party was at Stormont to "do the business".
She added: "Our determination is to make politics work. It is going to take all of the parties to make the politics work.
"It is going to need to be a sustainable and credible Government. It is going to need to be a Government that actually has equality at its core."
The UK and Irish governments have outlined their proposals to restore powersharing in Northern Ireland to the DUP and Sinn Fein.
As of Thursday morning, it was understood the three smaller parties involved in the talks initiative - the SDLP, Ulster Unionists and Alliance Party - were still awaiting full briefings about what the deal contains.
Another mandatory coalition executive can only be formed with the buy-in of the DUP and Sinn Fein.
The document represents the governments' joint assessment of what a compromise deal to resolve outstanding disputes over the Irish language and Assembly voting practices might look like.
They are urging the parties to sign up to the agreement ahead of Monday's talks deadline.
On that day, legislation to give civil servants extra powers to run the region's troubled public services expires and the UK government assumes a legal duty to call a fresh Assembly election.
