UUP MLA Rosemary Barton has accused Sinn Fein of the "glorification of terrorism" over comments made by a TD at the graveside of IRA man Sean South.
Sinn Fein, however, said it would not "take lectures" from the UUP, which "operated a one party, apartheid state for over 50 years".
Mrs Barton was speaking after Sinn Fein TD for Sligo-Leitrim, Martin Kenny, claimed that the failed terrorist attack on Brookeborough RUC station in 1957 in which two IRA men were killed, advanced the cause of Irish Unity.
Mr Kenny made the comments at a commemoration event on Sunday.
IRA men South and Fergal O'Hanlon were killed during the attack at Brookeborough RUC station on New Year's Day.
A Catholic RUC officer was also killed.
“What happened in Brookeborough in 1957 was not a brave stand," Mrs Barton said, "It was a failed terrorist attack in which a 14 strong heavily-armed IRA gang failed to take command of an isolated and poorly defended RUC station with only five officers inside.
“After the attack, in their rush to flee across the border again, the IRA abandoned the bodies of the dead Sean South and the dying Fergal O’Hanlon in a cow shed. A surgeon said at the subsequent inquest that if O’Hanlon had instead received medical attention in reasonable time his life could have been saved.
"Yet you won’t hear that in republican ballads or twisted Sinn Fein graveside orations."
She continued: "Sean South was a terrorist, a well-known fascist and an anti-Semite, and yet Sinn Fein politicians continue to fall over themselves to deliver the annual oration at his graveside.
"It’s no different to IRA Leader Sean Russell who died onboard a Nazi U boat in 1940 as he was being returned to Ireland, was buried at sea with full Nazi military honours complete with coffin wrapped in swastika flag, and who has a statue in his memory in a Dublin park at which Sinn Fein representatives have regularly eulogised him from."
Mrs Barton said that Sinn Fein continued to glorify the actions of the IRA.
“Unfortunately Martin Kenny TD is now just the latest to get involved in this twisted display of veneration. During his comments on Sunday Mr Kenny called Sean South a ‘legendary figure’," she said.
"He claimed that South died because he recognised that partition had been a ‘catastrophe’ and most hypocritically of all he then urged Republicans to act positively and to have an ‘inclusive dialog’, all the time standing by the grave of a bigoted IRA terrorist.
“This is just the latest example of Sinn Fein failing to understand for as long as they continue to glorify fanatics such as Sean South they will never be able to genuinely talk about their so-called Ireland of equals.”
In response to Mrs Barton's comments a Sinn Fein spokesperson said the Good Friday Agreement gives everyone the right to remember their dead with dignity and respect.
“Sinn Fein will take no lectures from a party which operated a one party, apartheid state for over 50 years and which used Special Powers to murder, detain and torture citizens, censored and banned political opposition and attacked peaceful protestors," the spokesperson said.