There will be no further meetings of Northern Ireland's power-sharing executive - unless there are "exceptional" circumstances - amid a political crisis over the alleged shooting of a man by the Provisional IRA.
Northern Ireland's First Minister Peter Robinson has said "business will not be as usual" until the situation is resolved "satisfactorily".
Father-of-nine Kevin McGuigan was shot outside his home in Belfast, last month, in what is believed to be a revenge attack.
Mr Robinson added: "In my view the Assembly is not fit for purpose as it stands today.
"Leaving aside the issue of the Kevin McGuigan murder it still wasn't fit for purpose. So, those issues have to be resolved.
"Unless those issues are resolved we will not have a functioning Assembly and we made it very clear without a resolution to these matters in the talks process our ministers' resignations will follow."
Crisis talks led by the British and Irish governments are due to begin at Stormont on Tuesday.
Northern Ireland's First Minister Peter Robinson has said there will be "no further" meetings of its power-sharing executive until the political crisis over the IRA is resolved.
The Democratic Unionists had failed in a bid for a four-week adjournment of the Assembly after police said members of the Provisional IRA shot a man dead in East Belfast.
But Mr Robinson said it could not be business as usual as members return from their summer break today.
Northern Ireland First Minister Peter Robinson has left hospital after suffering a suspected heart attack.
The Democratic Unionist leader spent four nights at Belfast's Royal Victoria Hospital where he underwent a procedure on Monday but has been allowed to return home to recover.
Senior DUP sources said the 66-year-old was in good spirits.
A spokesman said: "He was discharged this morning and is back at home. He is in good form and is happy to be home. His spirits are good."
Robinson used Twitter to thank the medics in the specialist cardiac unit.
Northern Ireland's First Minister Peter Robinson is in stable condition after suffering a suspected heart attack, a party official has said.
The Democratic Unionist leader was rushed to Belfast's Royal Victoria Hospital yesterday.
Speaking about the 66-year-old's condition, DUP Finance Minister at Stormont Arlene Foster said: "He has stabilised but still remains in hospital."
His health means he will miss an important Assembly debate on welfare reform which has been threatening to collapse the power-sharing institutions at Stormont.
Martin McGuinness has said that he is concerned to hear that First Minister Peter Robinson has been taken to hospital with a suspected heart condition.
In a tweet from his official account, the Northern Ireland deputy First Minister said that his "thoughts and prayers" were with Mr Robinson and his family.
David Cameron has wished the First Minister of Northern Ireland Peter Robinson a "speedy recovery" after he was admitted to hospital with a suspected heart condition.
Peter Robinson, the First Minister of Northern Ireland, has been rushed to hospital after suffering a suspected heart attack.
Mr Robinson, 66, was taken by ambulance to Belfast's Royal Victoria Hospital at just after 9am this morning.
Senior DUP sources confirmed the party's leader was being treated for a suspected heart complaint.
A hospital spokeswoman said: "Mr Robinson underwent a procedure this morning and is currently recovering in the Royal Victoria Hospital."
A DUP spokesperson said: "The First Minister felt unwell this morning and has been admitted to the hospital for some further tests."
Northern Ireland's First Minister Peter Robinson has made a public apology for any offence caused to Muslims by his defence of Pastor James McConnell.
Former Prime Minister Tony Blair engaged in a "deliberate deception by omission" by failing to tell the majority of politicians in Northern Ireland about the agreement his government struck with Sinn Fein to deal with on-the-run republicans, Stormont's First Minister has said.
Peter Robinson heavily criticised the conduct of the previous Labour administration as he addressed an emergency meeting at Stormont to debate the controversy over letters sent to more than 180 terror suspects informing them the authorities in the UK were not seeking them.
"The answer that there were no plans to legislate and no amnesty would be introduced was a deliberate deception, a deception by omission, for the Government could easily at that stage have indicated that there was an administrative process which included giving letters to OTRs," he told MLAs.
Stormont's Deputy First Minister Martin McGuinness said should the First Minister resign it would achieve "absolutely nothing".
Asked what he thought of Peter Robinson's threat to leave his post, he said: "I have to ask the question, what would that achieve?
"It could lead to an election and Sinn Fein has no difficulty with elections ... but what would that achieve? In my view absolutely nothing."
Mr McGuinness urged politicians to "stop the grandstanding" and stressed "steady leadership, responsible leadership" is needed going forward.