The DUP hit out at the Ulster Unionists’ decision to quit the Stormont government at the weekend, saying that political decisions should be taken “using their head rather than their heart”.
It came after senior members of the UUP officially voted to withdraw from Northern Ireland’s power-sharing Executive over claims the Provisional IRA still exists.
UUP leader Mike Nesbitt had proposed the exit in response to a police assessment that structures of the paramilitary organisation remain in place and some of its members were involved in a recent Belfast murder.
The UUP’s ruling executive approved Mr Nesbitt’s recommendation at a 90-minute meeting in the Park Avenue Hotel, east Belfast.
The vote, involving around 90 members of the party’s ruling body, was unanimous in favour of a Stormont Executive walkout.
Mr Nesbitt has said the revelations about the IRA have shattered trust in Sinn Fein and the UUP can no longer work in coalition with the republican party.
“The Ulster Unionist Party will be leaving the Northern Ireland Executive next week,” he said.
Mr Nesbitt said Danny Kennedy, the UUP’s one minister in a five-party administration comprising 13 ministers and two junior ministers, will formally resign this week.
A statement from DUP Finance Minister Arlene Foster, following the UUP’s decision, said their move would do little to pressurise Sinn Fein.
It said: “Republicans are the people with questions to answer and decisions to make.
“Sinn Fein has to decide if it is going to cling to its worn-out mantra that the PIRA has left the stage or if it is going to face down those elements in the republican movement who cling to criminality...
“Whilst some have taken a knee-jerk reaction to the news that PIRA members were involved in the McGuigan murder, this is a time for cool heads and considered action.
“People should be making decisions using their head rather than their heart.”
The UUP said it will now form an “opposition” in the Assembly – even though the power-sharing structures do not afford recognition for an official opposition to the mandatory coalition government.
The exit by one of the three minor partners in the administration will not in itself trigger the collapse of the Executive but it will throw its future into serious doubt.
The furore was sparked after PSNI Chief Constable George Hamilton said the PIRA still exists and some members were involved in the murder earlier this month of Kevin McGuigan, 53, in co-operation with others including a group calling itself Action Against Drugs.
Mr Hamilton has, however, said the PIRA is not engaged in terrorism – instead pursuing peaceful, political republicanism – and that there is no evidence the McGuigan killing was sanctioned by the IRA leadership.
Mr McGuigan was suspected by some in the republican movement of involvement in the murder of former IRA leader Gerard ‘Jock’ Davison in Belfast three months ago.
Police believe his killing was a revenge attack by Mr Davison’s republican associates.
Mr Nesbitt claimed Sinn Fein’s continued insistence that the IRA no longer exists means his party cannot trust what they say.
“Until that trust is restored and we find mechanisms to verify trust we cannot work in government with Sinn Fein,” he said.
Sinn Fein, which maintains the IRA has “gone away”, has accused the UUP of contriving a crisis in a bid to outflank the DUP ahead of next year’s Assembly poll.
It has repeatedly stressed that the IRA had “left the stage”.
The Ulster Unionists have also found themselves accused of hypocrisy by critics who have pointed to the fact the party co-operated with political representatives of loyalist paramilitaries as part of a pan-unionist/loyalist approach to a parading dispute last year.