Political talks aimed at saving Northern Ireland's crisis-hit power sharing government from collapse will take place in Belfast later.
Northern Ireland Secretary Theresa Villiers will convene discussions at Stormont House.
The negotiation process is expected to last four to six weeks and today's session will involve bi-lateral meetings between Ms Villiers and the individual parties. Irish government officials will also hold one-to-one meetings with the parties.
The latest crisis to beset the faltering administration was sparked by a murder linked to the IRA.
The Democratic Unionists have pulled all but one of their five ministers out of the Executive and DUP First Minister Peter Robinson has stepped down.
The Ulster Unionists have resigned their one ministerial post in what was a 13-ministry, five party coalition prior to the furore over the Kevin McGuigan murder.
Police have said current members of the IRA were involved in last month's shooting of Mr McGuigan in a suspected revenge attack for the murder of former IRA commander Gerard "Jock" Davison in Belfast three months earlier.
The disclosures about the IRA have heaped pressure on Sinn Fein to explain why the police assess that the supposedly defunct paramilitary organisation is still in existence.
Sinn Fein has insisted the IRA has gone away and has accused the two unionist parties of contriving a crisis for electoral gain.
The controversy escalated last week when three senior republicans, including Sinn Fein's northern chairman Bobby Storey, were arrested by detectives investigating the murder. All three were later released without charge.
But during the period they were being questioned, Mr Robinson stepped down and three of his DUP ministers quit the Executive.
Commenting publicly on his arrest for the first time on Sunday, Mr Storey accused unionists of trying to cynically exploit his "wrongful detention" to bring down power sharing.
He repeatedly insisted the IRA was no more - at one stage evoking the metaphor of a butterfly.
Police Service of Northern Ireland (PSNI) chief constable George Hamilton has said there is no evidence IRA leadership sanctioned the McGuigan murder. However, the region's senior officer said structures of the organisation still exist, albeit for political, not terror, purposes.
Mr Storey said he agreed with the assessment there was no IRA military footing, but he added: "Where I differ from the chief constable, is there is no role for the IRA, the IRA has finished, the IRA has gone. I think the chief constable and other perspectives out there see this in terms of the IRA being the caterpillar that's still there, where I think it's moved on, it's become a butterfly, it's flew away, it's gone, it's disappeared and they need to evolve to that as well."