The DUP has demanded that Gerry Adams and Martin McGuinness "fully admit the role they played within the IRA" and accused Sinn Fein of trying "to live in denial about their past".
The broadside from East Londonderry MP Gregory Campbell followed interviews given by Peter Rogers, a former IRA prisoner, to the BBC yesterday and the Sunday Independent last month.
Rogers claimed that Mr Adams ordered him to transport dynamite to Britain for a bombing campaign in 1980.
Rogers says they met him after he delayed taking it because he felt it was unstable.
The explosive sticks were weeping liquid nitro-glycerine, the active ingredient, and were too unstable to transport safely, he claimed in the newspaper. He said Mr McGuinness and Mr Adams met him in the sports ground of Trinity College Dublin to discuss the delay.
At the time, Rogers said he was working as a "logistics" man for the IRA, moving weapons and "personnel" between Rosslare, Wales and France. He worked for a while on the Brittany ferry before setting up his own parcel delivery service, partly as a cover for his IRA activities.
"When I met with them, Gerry wanted to know what the delay was," he said. He added that Mr Adams and Mr McGuinness listened to his concerns and held a brief conversation out of his earshot, before coming back to him.
"Gerry said: 'Look Peter, we can't replace that explosive, you will have to go with what you have and as soon as you can get it across, the better', so as far as I was concerned, I was given a direct order," he stated.
Rogers was moving the explosives in 1980 when his van was stopped by two gardai. He shot dead one of them, Detective Garda Seamus Quaid.
He is the latest in a string of former IRA members to say that Mr Adams was their superior officer.
This week Evelyn Gilroy, a former internee from west Belfast, said Mr Adams should be arrested and questioned about the murder of Jean McConville in 1972.
"The police should stop chasing those who were never in a position in the republican movement to order Jean McConville's execution and instead arrest the only person who was in that position – Gerry Adams," she said.
Mr Adams has consistently denied all this – putting it down to lies and black propaganda. Yesterday Sinn Fein said Rogers' claims were untrue.
Similar claims have been made by security forces North and South and by both governments. Taoiseach Enda Kenny has called for Mr Adams to admit he was on the IRA's 'army council'.
In 2001 Peter Robinson, now the First Minister, used Stormont privilege to name all alleged members of the IRA army council, including Mr Adams and Mr McGuinness.
Mr Campbell said: "The terror happened, it's now over. They need to admit their part in it, face whatever consequence there may be and move on."
Gerry Adams, the Sinn Fein president, has consistently denied being a member of the IRA, although several former IRA members have said he was, as have security forces North and South. He was charged with IRA membership in 1978 but released for lack of evidence. Martin McGuinness, the Deputy First Minister, says he is a former IRA commander but left the organisation in 1974, the second of two occasions when he was convicted of membership in the Republic.