AN annual republican commemoration parade to mark the deaths of IRA members has been described as "an attempt to rewrite history".
Unionists have reacted with fury to plans for Tyrone Volunteers Day to be staged in Castlederg this year, on August 11.
Those behind the event said it is intended to remember republicans killed throughout the Troubles. The 2013 event was launched at the spot where IRA men Seamus Harvey and Gerard McGlynn were killed 40 years ago by their own bomb.
Mr Buchanan said the planned parade, which is due to be considered by the Parades Commission, would pass a location where three members of the security forces were murdered by the IRA.
"Castlederg suffered immensely at the hands of IRA terrorism," he said. "This event is not just offensive to the victims of IRA terrorism, or to the unionist community, but to any right-thinking person in Northern Ireland."
He said he plans to meet with the Parades Commission.
He added: "Once again we see Sinn Fein trying to rewrite history where terrorists become 'volunteers' or 'patriots'.
"What is or was patriotic about killing other Irishmen who do not agree with your political agenda?"
Sinn Fein West Tyrone MLA Barry McElduff said the commemoration was always "poignant and dignified".
The Parades Commission is due to rule on the event on July 30.
"When one considers that in the Derg Valley area 29 victims lost their lives to terrorism... you would understand frustration and annoyance that Sinn Fein should target Castlederg for this event. Here we have Sinn Fein attempting to rub salt into the wounds of the bereaved."
Ross Hussey UUP MLA