Sinn Féin's Northern chairman Bobby Storey has been arrested and remains in custody along with two other well-known republicans in connection with the murder of Belfast republican Kevin McGuigan last month.

The arrests have generated political unrest within the Northern Ireland Assembly.

First Minister of Northern Ireland and leader of the Democratic Unionist Party, Peter Robinson, has stated that the DUP government ministers will resign from the Executive unless the Northern Ireland Assembly is adjourned in the wake of these arrests, leaving the Assembly once again in a state of crisis.

"As a consequence of today's events, we are seeking the recall of the Business Committee to consider adjourning the Assembly,” he said in his statement.

"If that does not happen or, as an alternative, the Secretary of State does not suspend the Assembly, then DUP Ministerial resignations will follow immediately."

"The DUP has made it clear it will not be involved in business as usual. Other parties must now step up to the mark and stop the Assembly from proceeding as if nothing has happened.

Robinson claims the resignations could take place as early as Thursday evening if government proceedings were not halted.

Such as move would cause the Northern Ireland power-sharing government to collapse.

Ex-IRA man Kevin McGuigan, father of nine, was murdered in the Short Strand area of Belfast last month, allegedly by IRA members. Police Service of Northern Ireland Chief Constable George Hamilton has stated that IRA members were involved in McGuigan’s death, although without the sanction of IRA leadership.

Storey and his fellow senior republicans, Brian Gillen and Eddie Copeland, are the latest in a string of 16 total arrests in connection with the murder. None of those arrested so far has been charged in relation to the murder, although one was charged for possession of a firearm.

The three men, aged 59, 58 and 45, were arrested in North and West Belfast on Wednesday morning.

“The three males are currently assisting officers at the Serious Crime Suite at Antrim Police Station,” said Detective Chief Inspector John McVea.

Sinn Fein leader Gerry Adams has expressed “grave concern” regarding the arrest of Storey and its impact on the current talks.

“At this stage I don’t want to go any further than to say that I have grave concerns about how all of this has developed, including the arrest of Bobby Storey,” he said.

Referring to Storey as his friend, Adams told how they first met “in the cages of Long Kesh when he was a very young man and the rest of it is a matter of history.”

He continued, describing Storey as “a person of great integrity,” a “valued member of our national leadership” and that he would be shocked if he was not released.

Bobby Storey has allegedly held several senior roles in the IRA. Following his internment in the 1970s, he served a long sentence for IRA offenses and was even referred to by the Ulster Unionist Party MP for South Antrim, David Burnside, as Head of Intelligence for the IRA.

Adams has insisted that there is no IRA structure still in existence and that Sinn Féin is presently the “only one republican organization involved in the republican struggle and in republican activism.”

Ulster Unionist Party leader Mike Nesbitt, however, argued: “There is one issue here – the fact that the IRA still exists, and Sinn Féin are in denial.”

He stated that the arrest meant a “question of the credibility of Sinn Féin” and that it would “not be business as usual”.

Traditional Unionist Voice leader Jim Allister has said that the latest arrest has brought the “murder investigation to the very heart of the DUP’s partner in government, Sinn Féin.”

“It is time for the DUP to wake up and come out from among them,” he added.

DUP leader Peter Robinson stated: “Hopefully the UUP will support us this time rather than voting with SF for business as usual.”

1/2) These events were predicted in my statement on Monday. No one can be above the law. That is why we sought adjournment of the Assembly.

— Peter Robinson (@DUPleader) September 9, 2015
The UUP walked out of government following the the PSNI assessment and have also vowed to remain outside of talks aimed at resolving the crisis.

Sinn Féin party member and Northern Ireland’s deputy First Minister Martin McGuinness has expressed his belief that Storey will be quickly released.

“He has played a leading role in Sinn Féin’s core peace strategy and is a longstanding and loyal supporter, defender and advocate of the peace and political processes,” McGuinness stated.

“We look forward with confidence to his early release.”

He also believes that UK Prime Minister David Cameron and Irish Prime Minister (Taoiseach) Enda Kenny will not approve the suspension of proceedings in the North.

"I think it would be a grave mistake from the British government to suspend these institutions. I think it would send a very negative message,” he said.

Sinn Féin Northern chairman Bobby Storey (left) standing with Deputy First Minister Martin McGuinness.Stephen Kilkenny / Photocall