Update 5.10pm: Sinn Féin has outlined details of a draft agreement it insists it struck with the Democratic Unionists before negotiations to restore Stormont powersharing collapsed.
Accusing the DUP of pulling the plug on the deal, Sinn Féin president Mary Lou McDonald said she needed to dispel "mistruths and inaccuracies" about what it contained.
She said the deal resolved the thorny language issue at the heart of the Stormont impasse with three separate pieces of legislation - an Irish Language Act, an Ulster Scots Act and an overarching Respecting Language and Diversity Act.
Mrs McDonald said no consensus was reached on the region's ban on same-sex marriage.
She said the text included a review of the Assembly's contentious voting mechanism - the Petition of Concern - and the establishment of a committee to look at the potential of drawing up a Bill of Rights for Northern Ireland.
Mrs McDonald said the two parties had also secured a commitment from the UK Government to commence a public consultation on stalled mechanisms to deal with the Troubles and to release funds needed to finance legacy inquests.
She said the parties also agreed that the Stormont Executive's sensitive justice ministry would start to be allocated in a conventional manner from 2022, rather than being a jointly agreed DUP/Sinn Fein nomination.
Mrs McDonald said the "draft agreement" was struck late last week.
"At that time we advised the DUP leadership that the deal should be closed before those opposed to it could unpick what we had achieved," said the Sinn Fein leader.
"We made it clear that if there was a delay there was every chance that the package would unravel.
"The DUP failed to close the deal and went on to collapse the talks process."
The two largest political parties in Ireland should be working together and not criticising each other to bring about devolved government in the North, the Tánaiste has said.
Simon Coveney said Fianna Fáil leader Micheal Martin's criticism of the Irish and UK Governments was not helpful and demonstrated a lack of understanding about the Stormont talks.
Talks to restore powersharing at Stormont collapsed on Wednesday after the DUP pulled out of the negotiations.
"We have a tradition in this house particularly between Fianna Fáil and Fine Gael of supporting each other and helping each other regardless of who is in government, in the context of protecting the fundamentals of the Good Friday Agreement and in terms of looking after the responsibilities we have towards people north of the border," Mr Coveney said.
"If Micheál Martin has an issue in terms of how we are taking on and performing those responsibilities he should talk to us about it as opposed to tweeting out within the hour of hearing the DUP statement yesterday trying to criticise two governments who are working in partnership to try to bring about devolved government again in Northern Ireland."
In a Twitter post Mr Martin said the continued failure of the two dominant political parties in the North to agree restoration of Government was "bitterly disappointing".
The continued failure of the two dominant political parties in the North to agree restoration of Government is bitterly disappointing. Politics is supposed to be about governing. The people are being badly let down. Detachment of both governments over last 6 years not helpful.— Micheál Martin (@MichealMartinTD) February 14, 2018
Sinn Féin's Pearse Doherty urged Fianna Fáil to reflect on the party's position.
"Micheal Martin has trotted out the same tired two problem party line while also blaming both governments," Mr Doherty said.
He added Mr Martin was pointing the finger of blame on everyone involved in the talks without lifting a finger himself.
"It's a disgraceful attitude and one that is completely at odds with the facts," Mr Doherty said.
The Donegal TD said he wanted to acknowledge the Tánaiste's efforts.
"You have been involved, you have been engaged, and it's important for us to say that," he said.
"So have your officials and we're very grateful for that."
Mr Doherty said Sinn Féin wanted the institutions back up and running and that direct rule from Westminster was not an option.
Sinn Féin is expected to outline the party's next move after powersharing talks in Northern Ireland broke down.
Democratic Unionist leader Arlene Foster has urged the UK Government to set a budget and make policy decisions in the absence of a devolved executive at Stormont.
The talks collapsed after the parties failed to clinch agreement on touchstone issues such as treatment of the Irish language.
Sinn Féin 's Northern Ireland chief Michelle O'Neill said the party had stretched itself and blamed the DUP for collapsing a process aimed at rebuilding coalition government at Stormont after a 13-month suspension.
The republican party wants a standalone 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.
Speaking on Wednesday, Mrs O'Neill said: "These issues are not going to go away.
"Myself and Mary Lou McDonald are engaged with both governments and will continue to do that and over the course of tomorrow we will set out a more fulsome response in relation to where we go from here."
Northern Ireland Secretary Karen Bradley said "substantive progress" had been made but conceded "this phase of talks has reached a conclusion".
Mrs Foster said attempts to find a stable and sustainable resolution had been unsuccessful.
She said: "We cannot and will not be held to ransom by those who have refused to form an Executive for over 13 months."
She added there was no "current prospect" of these discussions leading to a ministerial Executive being formed.
"It is now incumbent upon Her Majesty's Government to set a budget and start making policy decisions about our schools, hospitals and infrastructure.
"Important decisions impacting on everyone in Northern Ireland have been sitting in limbo for too long."
Months of endless talks have been held since powersharing collapsed early last year in a row over the DUP's handling of a botched green energy scheme.
Since then divisions over issues including Irish language rights, same sex marriage and how to deal with the legacy of Northern Ireland's troubled past have proved insurmountable.
Mrs O'Neill said: "Sinn Féin engaged, we worked in good faith, we stretched ourselves.
"We had reached an accommodation with the leadership of the DUP.
"The DUP failed to close the deal.
"They have now collapsed this process."
The implosion came despite Monday's last minute intervention by British Prime Minister Theresa May and Taoiseach Leo Varadkar, who travelled to Stormont for talks with the parties.
The British Government faces the prospect of having to step in and take previously devolved decisions in Northern Ireland.
Stormont departments have been without ministers for months and decisions need to be made speedily about the next financial year's public spending budgets.
Proposals for dealing with Northern Ireland's violent past involving extra money for historic investigations and truth-telling processes have also been delayed by the impasse and may fall to Westminster to implement.
Ms Bradley said "substantive progress" had been made but conceded "this phase of talks has reached a conclusion".
The Irish Government, co-guarantor of the 1998 Good Friday Agreement which largely ended violence, has said there can be no return to the direct rule of the period before that landmark accord.
Taoiseach Leo Varadkar said in a statement: "I very much regret the statement from the DUP. Power sharing and working together are the only way forward for Northern Ireland."