The report in An Phoblacht that the IRA had reservations about the Mitchell Principles was "a matter of major concern", the Taoiseach said. Mr Ahern added that, on Tuesday, Sinn Fein had signed up to the Mitchell Principles. "How the Government views this matter is that I expect the Mitchell Principles to be honoured by the entire republican movement."

The way forward was that matters would be dealt with by democratic and peaceful means and that the issue of disarmament would be dealt with by means devised by the commission. "That is the position, and I would expect the entire republican movement to honour that position."

The Fine Gael leader, Mr John Bruton, said the IRA and Sinn Fein were one and the same organisation in terms of political direction. "This interview in An Phoblacht is extremely disquieting and casts doubts on Sinn Fein's commitment to the Mitchell Principles.

"If that is the attitude of the IRA, then we are dealing with just an empty formula from Sinn Fein. I think it is very important that this matter be clarified with Sinn Fein."

The deputy leader of the Labour party, Mr Ruairi Quinn, who raised the matter on the Order of Business, said his party shared the Government's interpretation of what Sinn Fein had committed itself to on behalf of what it called the entire republican movement.

The leader of Democratic Left, Mr Proinsias De Rossa, said it was expected that the peace process was on the verge of a breakthrough next week, and it was of the utmost importance for the Government to clarify who spoke for the republican movement.

"Is it Mr Gerry Adams MP, or is it an unnamed, secretive person who gives an interview to An Phoblacht. I think it is important. It has every sense about it that it is an attempt to scupper the talks next week."

Asked by Mr Bruton if he was aware of the report when he spoke on the decommissioning Bill in the Dail on Wednesday, Mr Ahern said he had not been.