The Parades Commission has ruled that a contentious parades cannot proceed through the centre of Castlederg

A controversial Sinn Fein-backed march commemorating two IRA bombers in the Co Tyrone town they were intending to target has been restricted by the Parades Commission.

The body that adjudicates on contentious parades has ruled the republican event cannot proceed through the centre of Castlederg.

The Tyrone Volunteers Day event on August 11 will mark the deaths of Castlederg IRA men Seamus Harvey, 23, and Gerard McGlynn, 20, who died in 1973 when a car bomb they were understood to be transporting to the town detonated early. The explosion happened around three miles away at an Irish customs post across the border in Co Donegal.

Republicans in Co Tyrone hold the annual Volunteers Day to commemorate colleagues who died in the conflict. Rotating the venue and time to coincide with particular events and dates, Castlederg was chosen this year to mark the 40th anniversary of the deaths of the two IRA men. But the move provoked intense anger from some victims of IRA violence, who called for it to be banned completely.

Stormont Democratic Unionist First Minister Peter Robinson denounced the proposed event as "insensitive and inappropriate".

The organisers had volunteered to alter the original planned route of the march, to avoid the town's war memorial, but the Parades Commission has now placed further restrictions on the event, taking it away from the central Diamond area of Castlederg. It has also made clear that no paramilitary style clothing, flags or other symbols relating to a proscribed organisation can be displayed by participants.

A spokesman for the Parades Commission explained that the body no power to ban a parade outright. He said: "The proposed parade in Castlederg has generated an intense level of interest. Over the past few days the commission has considered a wide range of representations from parade organisers, political parties, victims and residents. The commission has also received around 500 emails and letters, many calling for the parade to be 'banned', a power which is not available to the commission under existing legislation.

"Although the original route was revised, on the basis of the representations received the commission has concluded that if the parade were to proceed as notified it would have a damaging effect on community relations in the town. Consequently, the commission has issued a determination to restrict the parade's route away from the 'Diamond' area, including the Cenotaph, in Castlederg."

In the wake of the Commission's announcement, Ulster Unionist leader Mike Nesbitt called on Northern Ireland Secretary Theresa Villiers to ban the parade entirely.

In a letter to Ms Villiers, he wrote: "The Ulster Unionist Party urges you to act now and ban this parade and commit to banning all future parades that would have the clear intent of celebrating or glorifying those who engaged in acts of terrorism."