British and Irish government ministers are set to attend a memorial service for the 25th anniversary of the Omagh bombing.
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.
In 2009, following a landmark civil case taken by families of some of the victims, a judge ruled that five people were all liable for the bomb and ordered them to pay damages.
This year’s memorial service comes following the granting of an independent statutory inquiry into the atrocity.
The service is taking place on the closest Sunday to the anniversary date of August 15.
Northern Ireland Office minister Lord Caine and Irish Minister of State for European Affairs and Defence Peter Burke are among those to attend the event at the memorial garden in Omagh later.
A prayer will be read in English, Irish and Spanish during the service in respect of the victims of the bomb, which include a child from Spain and children from Co Donegal.