Secretary of State Theresa Villiers has called on organisers of a contentious republican parade marking the deaths of two IRA men to 'call it off'.
She was speaking after a meeting with victims group - the Derg Valley Victims Voice - ahead of this weekend's planned march through Castlederg.
The Sinn Fein backed parade on Sunday to commemorate two IRA bombers in the Co Tyrone town they were intending to target, has already been branded insensitive and inappropriate.
The Tyrone Volunteers Day event will mark the deaths of Castlederg IRA men Seamus Harvey and Gerard McGlynn who died in 1973 when a car bomb they were understood to be transporting to the town detonated early.
Theresa Villiers has now called on those behind the march to call it off, which she said was "damaging to community relations".
"There is no doubt that this deeply insensitive parade is causing great hurt and distress to many victims of terrorism in the west Tyrone area and the rest of Northern Ireland," she said.
"Everyone who wants to build a genuinely shared future for Northern Ireland needs to consider the impact of their actions on people from different parts of the community.
"This parade is damaging to community relations and even at this late stage I would call upon the organisers to think again and call it off."
But she said she lacked power to ban the parade.
"On the issue of legal powers to ban the parade, these are restricted and narrowly defined," she said.
"The criteria set out in legislation that would enable me to intervene are not satisfied in this case. I realise that will disappoint many but I am bound by the law."
Ms Villiers also with met with a number of unionist politicians during today's talks, including DUP MLA Arlene Foster.
Arlene Foster said Sunday's parade would see "Sinn Fein duplicity reach a staggering level".
Castlederg will be the scene of both a loyal order parade and a republican commemoration, both accompanied by counter protests.
The republican parade has been rerouted but still passes the site of two IRA murders, while loyalist groups will protest along the route.
Meanwhile, the Orange Order is expected to protest against a dissident republican parade through the centre of Belfast on Friday.
A 5,000-strong dissident republican rally to mark the anniversary of internment has been given the go-ahead without restrictions by the Parades Commission.
IRA men Seamus Harvey (23) and Gerard McGlynn (20) died when the bomb they were transporting to Castlederg detonated prematurely on August 11, 1973. This weekend's march marks the 40th anniversary of their deaths. The Parades Commission gave it the go-ahead. However the march has been re-routed to avoid a war memorial in the town's Diamond. There have been calls from victims and unionist politicians to cancel the event.
Martin McGuinness responded to criticism of the Tyrone Volunteers Day parade in Castlederg by arguing last week: "The parade which is about to take place is a parade that is absolutely and totally confined to the nationalist and republican areas of the town and it doesn't impinge on the unionist communities."
Let me go over a few basic lessons for those slow at the back. This thing isn't called a peace 'process' for nothing. We aren't going to wake up one day and find, hey, it's all over. The business of 'peace' is about constant, daily, persistent acts of self-control. Yes, there is a reservoir of pain and hurt and fury and disappointment and frustration and grief big enough to drown Europe. We all know this.