Sinn Féin's Stormont leader Michelle O'Neill "reopened wounds" by her attendance at a commemoration for eight IRA men shot dead by the SAS, the DUP's Sir Jeffrey Donaldson has said.
Ms O'Neill defended her decision to attend a commemoration for eight IRA men shot dead by the SAS in Loughgall in 1987.
An innocent civilian was also killed.
Michelle O'Neill spoke on Sunday at a memorial event marking 30 years since the ambush.
Mr Donaldson said all families had a right to remember their dead, but that the event on Sunday was "more than that".
"It was an opportunity for Michelle O'Neill to say the murder of innocent people by the IRA was wrong - to reach out to their families," he told BBC Radio Ulster's Talkback programme.
"Michelle O'Neill failed to acknowledge and recognise the suffering of IRA victims, she failed to reach out to them.
"It reopened wounds for many of those people to hear the person who aspires to be the Deputy First Minister in Northern Ireland defend the IRA."
Unionists and victims had reacted angrily to the move by Ms O'Neill.
However, she said everyone had a legitimate right to remember their dead.
She told people gathered for the commemoration at Cappagh, County Tyrone, that victims and survivors of the Troubles in Northern Ireland who sought justice and truth, must be given the strongest possible support and assistance.
"While much of our history has been marked by sadness and tragedy, we now have a unique opportunity to be the authors of a new, peaceful, and democratic future," she said.
"This does not mean we forget our past. Everyone has a legitimate right to remember their dead, tell their side of the story and share their experiences, and hurt, of that time, without being demonised.
"I challenge our opponents to stop fighting a war which is now over. There is an onus on all of us to move forward to create a free, just and equal society - together."
Ms O'Neill said she had been criticised by unionists and the media for commemorating IRA volunteers, but she was an Irish republican.
"I see no contradiction whatsoever in commemorating our republican dead while reaching out to our unionist neighbours to build the future - Orange and Green together on the basis of full equality and mutual respect," she said.
Sinn Féin's Gerry Kelly told BBC Radio Ulster's Talkback that Mr Donaldson "needed to realise that there needs to be equality for families of victims".
"They need to be allowed to grieve in their own way, no-one comes on and argues that people cannot be involved in the UDR (Ulster Defence Regiment), or the British Army or the SAS, or indeed loyalist murder squads."
Undercover soldiers killed eight members of the Provisional IRA's East Tyrone unit at Loughgall in May 1987.
It happened as they approached Loughgall RUC station in County Armagh with a bomb in a hijacked digger.
The IRA men shot were: Jim Lynagh, Padraig McKearney, Gerard O'Callaghan, Tony Gormley, Eugene Kelly, Patrick Kelly, Seamus Donnelly and Declan Arthurs.
The SAS also shot Anthony Hughes and his brother was badly wounded.
In 2014, Mr Hughes' family received a fully government apology confirming he was entirely innocent of any wrongdoing.
In 2001, the European Court of Human Rights found the rights of those killed at Loughgall had been violated.
Earlier this week, during a visit to a Catholic grammar school to meet Irish language students, DUP leader Arlene Foster criticised Ms O'Neill's decision to attend the commemoration.
"It is disappointing that when I am trying to make this a shared place for everybody in Northern Ireland that other leaders are doing things that frankly are wrong and backward looking," Mrs Foster said.
"I am thinking of what is happening in Loughgall on Sunday and I think that is something that Sinn Féin needs to reflect on.
"We have heard a lot during the election about respect and they need to understand what that means in terms of the past and in terms of the future, as people look to the future here in Northern Ireland."