The DUP has said "huge differences" still remain to be resolved before power-sharing at Stormont can be restored.
Northern Ireland's five main political parties have met for the first of a series of round-table crisis talks in an attempt to find a way to end the year-long political stalemate.
Following the meeting, which lasted little over an hour, the DUP's Simon Hamilton said: "We have huge differences between the parties on a range of key issues and we have been working through those issues.
"We have made some progress on many but there are some big and, in some cases, quite significant gaps.
"We want to get this assembly back up and running again. We want to do that on the basis of accommodation that is fair, one that allows a sustainable Stormont to be restored."
Sinn Féin senior negotiator Conor Murphy said: "This process will come to an end in the next short while and we will make a judgement then as to whether a deal is possible or not.
"We entered in to what we were told and agreed was a short and sharp process to see was an agreement possible.
"We were told this is the last chance and we accept that the talks cannot go on forever."
The British government agreed that difficult issues remain to be resolved, but it insisted that "progress has been made" and an agreement is achievable.
Minister for Foreign Affairs Simon Coveney attended the talks, along with recently appointed Northern Secretary Karen Bradley.
In a statement, the Department of Foreign Affairs said it shares the British government's "assessment that there is a shared commitment across all parties to see the devolved institutions operating effectively in the interests of all the people of Northern Ireland".
It said: "Time is short, but the prize is one worth stretching for."
Ms Bradley is due to provide the British parliament with an update on the progress of the talks on Wednesday.
However, Ulster Unionist MLA Steve Aiken said there had been "no progress at all".
He said: "Today we have a situation where we are being asked to give them even more time and we are not being given the opportunity to discover what the DUP and Sinn Féin have been working towards."
Alliance Party leader Naomi Long warned: "There is an opportunity still for a deal to be done, but at the moment I do not think we could have any confidence that a deal could be done if the process continues as it has."
The SDLP's Nichola Mallon added: "What we got today was more of the same."
Northern Ireland has been without a power-sharing government for a year, after the coalition led by the DUP and Sinn Féin collapsed.
Discussions began in January in an attempt to break the impasse at Stormont and restore the executive.