The UK and Irish governments must inject "leadership and energy" into last-ditch talks to restore powersharing in Northern Ireland, Sinn Fein has said.
Claiming the Democratic Unionists (DUP) were still standing in the way of a deal, Sinn Fein's John O'Dowd told the governments to ramp up their involvement in the stalled negotiations.
An impasse over republican demands for legislation to protect Irish language speakers is one of the main impasses. The DUP is willing to legislate, but only if Ulster Scots speakers are included in any Act - a condition Sinn Fein has rejected.
The parties have until 4pm on Thursday to nominate ministers to a new coalition executive or they face the prospect of some version of direct rule be imposed from Westminster or yet another snap Assembly election.
Emerging from the talks venue at Stormont Castle in Belfast, Mr O'Dowd questioned the merit of extending the deadline to facilitate further discussions.
"Timescale is not the issue," he said.
"It is a willingness by the participants in the talks to resolve the outstanding issues."
The Sinn Fein negotiator added: "There is clearly an onus on the governments to inject energy into these talks, to inject leadership into talks and ensure the outstanding issues are resolved in the time-scale we have left to us."
The DUP has told the republican party to stop indulging in "high-wire acts" and get down to the job of delivering for the people.
Ulster Unionist (UUP) leader Robin Swann said his party would not provide "cover" for the DUP if it signed up to an Irish Language Act.
Revealing that the DUP and Sinn Fein did not attend a scheduled round table meeting inside the castle on Wednesday afternoon, he also warned that his party should not be taken for granted.
He said there were many issues the UUP wanted to raise, including mechanisms for dealing with the legacy of the Troubles and pensions for conflict victims.
"Our party will not be taken for granted in these talks or the formation of any executive," he said.
Sinn Fein has hinted movement was possible on one precondition - its opposition to DUP leader Arlene Foster returning as Stormont first minister while a public inquiry into a botched green energy scheme is ongoing - if the DUP gave ground on other matters.
Mrs Foster was forced from office in January when Sinn Fein's then deputy first minister, the late Martin McGuinness, quit in protest at the DUP's handling of the Renewable Heat Incentive (RHI) - a scheme that left the administration facing a £490 million overspend.
His move triggered a snap assembly election in March.
A number of attempts to restore powersharing between the five main parties following that poll floundered, with three UK Government deadlines for a deal having already been missed.
The DUP's Edwin Poots (PA)
Earlier, Northern Ireland Secretary James Brokenshire said failure to strike a powersharing deal would have "profound and serious" implications.
He told MPs at Westminster: "Our focus is on seeing that an Executive is restored and I have been clear on not wanting to pre-empt what may happen should that not be the case.
"Obviously there would be profound and serious implications in that context."
He said he would work with all parties to see that the issues were considered carefully.
Senior Democratic Unionist negotiator Edwin Poots said his party was ready to re-establish devolved government on Thursday.
"We will be happy to run D'Hondt (to select ministers) tomorrow and continue with negotiations in a fair and reasonable manner to get the solutions.
"It is up to Sinn Fein if they wish to do that, or if they want to break through the deadline that is a matter for them, but we are happy to nominate ministers tomorrow."
He said the Irish language was a touchstone issue.
"We want to show absolute respect to people's language and culture and are working extremely hard to identify what people's bottom lines are and how we can move those issues forward.
"Education and health is a greater priority for me than languages.
"Sinn Fein have identified language as their highest priority.
"We want to work with them to try to find a way through."
The British and Irish Governments are leading the talks as co-guarantors of the peace process.
An Irish Government source confirmed Dublin's "consistent position" over many years had been in favour of an Irish Language Act in Northern Ireland.
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here