The Northern Ireland Office said in a statement that violent attacks "inevitably raise questions" over the position of the Progressive Unionist party and Ulster Democratic party. The parties are seen as speaking for, respectively, the Ulster Volunteer Force and Ulster Defence Association, both of which are illegal paramilitary organisations.
The statement is seen as a response to Monday's boobytrap attack on a family in Larne, Co Antrim. A hand grenade exploded underneath a van holding a Catholic couple and their five-month-old baby, but none of them was injured. The UVF has a significant presence in the town.
The NIO had received a barrage of criticism for its perceived reluctance to attribute two previous boobytrap attacks to loyalists, even though security sources held them responsible, and loyalists themselves privately admitted involvement.
Officially, the Government and the fringe parties maintain that the loyalist ceasefire is holding. But it is evident that the NIO has become increasingly worried about its public position, which was rendered highly uncomfortable following RUC Chief Constable Ronnie Flanagan's acknowledgement that the first two bombs were planted by loyalists.
The NIO statement said: "The Government shares the increasing public concern that has arisen as the result of recent car- bomb attacks, the first two of which have been attributed by the Chief Constable to loyalist extremists. Those incidents, and possible that at Larne yesterday, inevitably raise questions over the position of the two parties associated with the loyalist paramilitaries."
It is open to participants in the political talks to raise the issue, and possibly seek the expulsion of the loyalists, during a plenary session to be held on Monday next. At the moment however the signs are that most parties are reluctant to press the issue.
The Ulster Unionist MP Ken Maginnis said his party would not seek their expulsion, saying there had been a significant contrast in the leadership being given by loyalist political spokesmen and the Sinn Fein leadership. But he added: "Obviously there could come a point when the weight of activity overrides that point of view."
Ian Paisley jun of the Democratic Unionist party said his party was waiting for the Government to take the initiative. He added: "Quite obviously the British government want everyone else to do their dirty work for them. We are saying to them 'You have the statements from the RUC, you are a participant in the talks, you bring forward the indictment'."