The car bombing by dissident republicans in the town of Omagh on 15 August 1998 claimed 29 lives, including a woman pregnant with twins, her 18-month-old daughter and her mother - several generations of one family.

Three hundred others were injured.

At the service, the names of all the victims and their ages were read out.

Sixteen of those who died were under 25.

No-one has been criminally convicted of the attack by breakaway Irish republican group the so-called Real IRA. But there will be an independent statutory inquiry into the atrocity.

In 2009, following a landmark civil case brought by relatives of some of the victims, a judge ruled five people were liable for the 500lb bomb and ordered them to pay damages.

The deadly explosion happened just four months after the historic Good Friday peace agreement which was based on the idea of co-operation between communities.

The deal, brokered by the UK, the Republic of Ireland and the US, led to a new government for Northern Ireland being formed, representing nationalists and unionists.

The memorial service, attended by among others, Northern Ireland Office minister Lord Caine and Irish Minister of State for European Affairs and Defence Peter Burke, took place on the closest Sunday to the anniversary date.

One of those speaking at the memorial garden gathering was Michael Gallagher, whose son Aidan was among the Omagh victims.

He expressed thanks to everyone involved in putting the service together and to those who have supported families in the years since the attack, including Father Kevin Mullan.

Read more:
Terrorist threat still hangs over Northern Ireland

Mr Gallagher said: "I cannot finish without reflecting on those who we have lost along the way, who were instrumental in rebuilding the hearts and minds of those affected by this atrocity.

"Earlier this year sadly, we said goodbye to Father Kevin Mullan. Father Kevin was present on the 15th of August, 25 years ago. He attended the victims on the scene, anointing with the last rites and providing comfort to the injured and the dying."

He added: "We will always be indebted to him for the strength and compassion and courage he demonstrated on the day and the months and years and decades that followed.

"It didn't matter to him if you worshipped in a church or chapel. His wisdom and influence filtered into the community as he worked tirelessly, unselfishly to create unity and togetherness.

"We will remember him as a decent and honourable human being, which will impact on generations to come."

Twenty-five years since the attack, the spectre of terrorism still hangs over Northern Ireland - the threat posed by dissident groups such as the New IRA deemed severe.

The self-styled New IRA is a conglomerate of breakaway factions still actively engaged in what they call "the armed struggle".

Security services estimate there are fewer than 100 members, but they have demonstrated their deadly capability by carrying out bombings and shootings.

Earlier this year, they grabbed headlines with another attack in Omagh - the attempted murder of Detective Chief Inspector John Caldwell.

In 2019, one of their gunmen opened fire on police during a riot in Derry's Creggan estate, fatally wounding the journalist Lyra McKee, 29.