By PA reporter
The President of Ireland is calling for a "culture of peace" as Omagh marks the 20th anniversary of the worst single atrocity of the Northern Ireland conflict.
Twenty nine innocents, including a woman pregnant with twins, died when a massive car bomb ripped through the Co Tyrone town just months after the 1998 Good Friday peace agreement was supposed to have largely ended violence.
The Real IRA was blamed for the carnage after inaccurate warnings meant police evacuated shoppers towards the bomb site.
Twenty years later, nobody has ever been convicted of the murders.
Relatives of the dead will gather on the spot this afternoon for a short ceremony led by Omagh Churches Forum at Market Street.
At 2.55pm a bell will ring 32 times, reflecting the 31 lives lost, and an additional peal to remember all who have lost their lives through similar atrocities.
The bell will stop tolling at 3.10pm, the time the bomb exploded. It'll be followed by a two minute silence.
Omagh 20 years on...The human cost. Patricia McLaughlin’s son Sean was one of the child victims: "It breaks your heart, you'd love to know what he'd be doing now if he was still here - but that's just not going to happen." Bomb attack anniversary on air throughout the day. pic.twitter.com/s9igqcYxQt
— Q Radio News (@qnewsdesk) August 15, 2018
Patricia McLaughlin's son Sean was one of the child victims of the 1998 attack that killed 29 people including a woman pregnant with twins.
The 12-year-old had been with a group from County Donegal who were enjoying a day trip to Omagh before the Real IRA bombers struck.
Irish President Michael D Higgins said: "As we recall with deep sadness the deaths and the injuries at Omagh, we should use this moment to recognise the many ways in which we are all connected and the many ways in which we have sought to make peaceful progress over the last two decades.
"May we use this anniversary as we honour the victims, to re-emphasise the importance of building a culture of peace and tolerance on our island."
The victims included Protestants and Catholics, tourists from Spain and others on a day trip from the nearby Republic of Ireland.
One of the biggest police manhunts in history unfolded, but criticism of the police investigation led to unfulfilled calls for a public inquiry.
Two faced prosecution for murder but were not convicted.
Catholic Bishop of Derry Donal McKeown held a special Mass in the town on Tuesday evening.
He told parishioners at the Sacred Heart Church: "Your memorial here is a monument to all the innocent who were torn from us by violence in our community.
"Combatants do fighting but it is mostly civilians who do the dying."
Twenty years on, the Stormont power-sharing administration which was a centrepiece of the Belfast Agreement is suspended with little sign of its restoration.
Those who were killed were:
James Barker, 12
Seán McLaughlin, 12
Oran Doherty, 8
Fernando Blasco Baselga, 12
Rocío Abad Ramos, 23
Geraldine Breslin ,43
Gareth Conway, 18
Breda Devine, 1
Aidan Gallagher, 21
Mary Grimes, 65
Brenda Logue, 17
Brian McCrory, 54
Seán McGrath, 61
Jolene Marlow , 17
Avril Monaghan, 30 (was pregnant with twins)
Maura Monaghan,1
Elizabeth Rush, 57
Philomena Skelton,39
Deborah-Anne Cartwright,20
Esther Gibson,36
Olive Hawkes, 60
Julia Hughes,21
Ann McCombe, 48
Samantha McFarland, 17
Alan Radford, 16
Veda Short, 56
Fred White, 60
Bryan White, 26
Lorraine Wilson,15