Alliance leader Naomi Long, a former justice minister in the Northern Ireland Executive, has appealed for anyone with information relating to the August 1998 Omagh bombing to come forward.
Ms Long’s comments follow a commemoration service over the weekend and before a Tuesday gathering of some of those bereaved by the incident to mark the 25th anniversary of the Real IRA attack.
The dissident republican attack in 1998 devastated the Co Tyrone village, killing 29 people, including a woman pregnant with twins, and injuring hundreds of others.
It came just months after the historic Belfast/Good Friday Agreement and was the greatest loss of life in a single incident in Northern Ireland’s troubled past.
No-one has ever been criminally convicted of the attack.
Ms Long said: “The announcement by the UK Government earlier this year of an independent statutory inquiry into the bombing will have brought some relief for grieving families but nothing can truly ease the pain of the horrific loss they suffered.
“That the dissident republicans behind this crime have yet to be brought to justice simply adds to the anguish.
“Those bereaved and injured by the Omagh bomb have a right to know the full facts surrounding the tragic event and even now, 25 years on, I would appeal to anyone with information to come forward.
“I also call on those still engaged in violence to end their destructive campaigns.”
SDLP West Tyrone MLA Daniel McCrossan also paid tribute to the “strength of the Omagh bombing families”.
He added: “The events of August 15 1998 have cast a long shadow over the town of Omagh.
“The scars still run deep, for many the pain is as a real today as it was 25 years ago, when life changed forever for hundreds of people right across this community.
“I cannot adequately express how proud I am of how this community has responded in the years since the bombing.
“Instead of being consumed by bitterness and hatred, the Omagh families have shown strength, dignity and a humanity that couldn’t reasonably have been expected of them in these awful circumstances.
“It has been an honour and privilege to get to know them over the years and to support them in their never-ending quest for truth and justice.”
He said it was “deeply distressing” that the community was still waiting for the commencement of an inquiry into the bombing.
He added: “Families have already waited far too long, many family members of victims have passed away and we need to see this inquiry start as soon as possible.
“There can be no stone left unturned.”
