Arlene Foster has said she is disappointed that Sinn Fein's Stormont leader is attending a commemoration for eight IRA members killed by the SAS in Northern Ireland.
Michelle O'Neill will address a republican parade and memorial event on Sunday marking 30 years since the ambush by elite troops in Loughgall in Co Armagh.
DUP chief Mrs Foster met Irish language students in Northern Ireland as part of a bid to learn more about the language as part of efforts to restore devolved powersharing with nationalists.
She said: "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.
"I am thinking of what is happening in Loughgall on Sunday and I think that is something that Sinn Fein needs to reflect on because we have heard a lot during the election about respect and they need to understand what that means in terms of the past and indeed in terms of the future as people look to the future here in Northern Ireland."
The SAS intercepted the IRA unit as it launched an attack on a police station in the village in May 1987 and riddled its van with bullets.
Sinn Fein considers those who died as martyrs; many unionists as terrorists.
Controversy has long surrounded the ambush, which also killed a bystander, amid claims the gunmen continued to fire on a number of the IRA men with heavy machine guns as they lay wounded on the ground.
A lawyer for the bereaved has claimed the servicemen acted excessively.
The DUP has accused Sinn Fein of demonstrating little respect to the victims of IRA terrorism, choosing instead to describe a group of men who went out with the sole intention of murder and mayhem as martyrs.
The Ulster Unionist Party’s Justice spokesperson, Doug Beattie refuted Sinn Fein’s use of the word ‘martyrs’ to describe those killed at Loughgall.
“I have always taken the view that everybody has the right to remember their dead, but that must be done with sensitivity and people should not seek to re-write history in the process. In attending this particular commemoration, Michelle O’Neill is re-affirming Sinn Fein’s deep rooted link to this group, described as ‘streetwise homicidal maniacs’ in Dr William Matchett’s recent book ‘Secret Victory, The Intelligence War that beat the IRA," he said.
“The truth is that the IRA men who chose to turn up at Loughgall on 8 May 1987 were heavily armed, all wearing body armour and were extremely dangerous. They were not ‘martyrs’, they were criminals. They were there to commit murder, and murder is a crime.
“This particular gang had been involved in previous attacks on police stations. Two police officers were murdered in an attack on the RUC station in Ballygawley on 7 December 1985 and the RUC station at The Birches was attacked on 11 August 1986. The attack on Loughgall was to follow the same plan. Indeed, one of the weapons recovered from the terrorists killed at Loughgall, had been taken from an RUC officer murdered in the Ballygawley attack."
The IRA members killed were Jim Lynagh, 32; Padraig McKearney, 32; Gerard O'Callaghan, 29; Tony Gormley, 25; Eugene Kelly, 25; Patrick Kelly, 32; Seamus Donnelly, 19; and Declan Arthurs, 21.
