A man whose 13-year-old sister was killed in the Shankill bomb has slammed Mary Lou McDonald for justifying the IRA campaign.
Gary Murray said that the Sinn Fein president was "no different to Gerry Adams".
Mr Murray's sister Leanne was one of nine people killed in the 1993 Shankill bomb. One of the IRA bombers also died.
Mr Murray said: "Does Mary Lou McDonald think that the Shankill bomb was justified? That Omagh and Enniskillen were justified? She needs to immediately apologise to victims."
In an interview with the Sunday Independent, Ms McDonald justified the IRA campaign and said there was a chance she may have joined the Provisionals had she lived in Northern Ireland.
Meanwhile, the son of an Irish soldier shot dead by the IRA has welcomed Ms McDonald saying that his father's murder was "absolutely wrong". But he has asked her to instruct IRA members to help the family get justice. David Kelly said he was perturbed by the Sunday Independent interview in which she justified the IRA campaign.
Private Patrick Kelly was part of an Irish Army and Garda patrol searching Derrada Wood at Ballinamore, in December 1983, not far from Leitrim's border with Fermanagh, for kidnapped Quinnsworth supermarket boss Don Tidey, who had been abducted three weeks earlier.
Speaking on LMFM radio on Monday, the Sinn Fein president referred to Private Kelly's murder.
"Every life lost was a tragedy for the family and friends of that person," she said.
"The loss of a serving member of the defence forces, of Oglaigh na hEireann, of his father, was wrong, absolutely wrong, should not have happened in any set of circumstances."
Welcoming Ms McDonald's words, David Kelly said: "I hope that she tries to help my family secure justice. She must urge anyone in IRA ranks that can assist us get justice to come forward.
"But I am very concerned that someone who has ambition to become Taoiseach would have considered joining an illegal organisation that murdered my father and 1,700 others."
Mr Kelly was nine when his 36-year-old father was killed. He once called Martin McGuinness a liar to his face over the murder for which he has desperately sought answers.
Pte Kelly was shot dead along with a trainee Garda, Gary Sheehan, by members of the four-man Provo gang.
DUP MP Sir Jeffrey Donaldson said: "For Mary Lou McDonald to differentiate between one IRA murder and another is quite incredible and requires immediate clarification from the Sinn Fein leader.
"As far as we are concerned, every single PIRA murder was wrong and is unjustifiable whether it was a soldier, police officer, man, woman or child,
"If Mary Lou is going to justify one and not another then she needs to speak further as there are families all across the British Isles who were bereaved by the PIRA."
In the Sunday Independent interview Ms McDonald stated that she did not see IRA members as terrorists. "I do accept that IRA actions hurt and killed a great many people," she said. "I also know that actions of state forces and actors and loyalist paramilitaries similarly caused grief and loss. For me, the important piece of this is not to label any people as 'terrorists' but to accept that there was a political context, there was a reason."