Concern was mounting last night that the fallout from the Castlereagh break-in, alleged IRA intelligence-gathering on senior Conservatives and last Wednesday's murder of a Co Tyrone taxi-driver could precipitate a fresh political crisis.
The IRA attempted to provide some political reassurance yesterday by again insisting that it was not responsible for the Castlereagh raid and by stating that its ceasefire was intact and that it was not targeting individuals for attack.
"The IRA ceasefire remains intact. The IRA is not targeting. The IRA poses no threat to the peace process," a spokesman for the organisation told the BBC yesterday.
A number of unionist politicians nonetheless called for sanctions against Sinn Féin. Some demanded the expulsion from the Executive of the two Sinn Féin ministers, Mr Martin McGuinness and Ms Bairbre de Brún.
This is putting increasing pressure on Mr David Trimble at a time when - in the aftermath of the second act of IRA decommissioning - he believed he was strengthening his hold on his party.
The Sunday Telegraph and Scotland on Sunday yesterday added to the political unease by reporting that the IRA had imported a consignment of weapons from Russia last year.
The allegations are causing particular nervousness among Ulster Unionists. Anti-Belfast Agreement elements in the UUP are now putting pressure on Mr Trimble to take action against Sinn Féin.
Speaking at a press conference in Dublin, the Sinn Féin president, Mr Gerry Adams, described the suggestions contained in the British Sunday newspapers as "silly" and "stupid".
Meanwhile, a senior republican who was questioned by police about the murder in Donaghmore, Co Tyrone, of taxi-driver Mr Barney McDonald was yesterday released without charge. The McDonald family has blamed the IRA for the killing.