The Government has said it is committed to pressing Britain into giving an international judge access to files on the worst day of atrocities in the Troubles.
On the 42nd anniversary of the Dublin-Monaghan bombings, which killed 33 people including a pregnant woman at full term, Foreign Affairs Minister Charlie Flanagan said he would continue to demand the original police and security papers be opened.
“The government will continue to actively pursue this objective, and we have made it a commitment in the new Programme for Government,” the minister said.
A wreath-laying ceremony – organised by Justice for the Forgotten, which campaigns for an investigation into alleged British state collusion in the 1974 massacre – was held at the memorial on Talbot Street in Dublin, where one of the three bombs in the capital exploded.
Two others bombs were detonated on Parnell Street and South Leinster Street in the co-ordinated attacks in the middle of the evening rush hour on May 17.
About an hour and a half later the fourth no-warning bomb was set off in Monaghan town with the atrocities blamed on the Ulster Volunteer Force.
A floral tribute on behalf of U2 was left at the memorial with the note: “Justice for the Forgotten. To all the victims and their families. In our thoughts and prayers on this day.”
The band displayed photos of the victims on a huge screen during last year’s Innocence + Experience tour as a backdrop to the song Raised By Wolves, written about the 1974 bombings.
Band members Bono and Adam Clayton attended an anniversary mass in Dublin ahead of the wreath laying.
Alan McBride, whose wife Sharon was blown up in the IRA Shankill bomb in 1993, addressed the relatives and campaigners at the memorial and said the question of truth and justice is as relevant today as it was in 1974.
“The question of dealing with the past in NI is not really about money, it’s about political will. There has always been obstacle and barrier that we have to get beyond,” he said.
“At the moment they seem to be raised by the British Government in relation to national security.”
Mr McBride, who works with the Wave Trauma Centre in Belfast supporting victims of violence, said: “Truth and justice cannot be the property of the few.
“The families need truth, they need justice and they need support. This is not going to go away.”
A spokeswoman for the British Government said it was examining if it could give “any further assurance” on the issue of files being opened.
“The bombings were horrific terrorist atrocities and our sympathy is with the families who lost loved ones and survivors who carry mental and physical scars to this day,” she said.
The Government pointed to the stalled legacy bodies in Northern Ireland which will include a new Historical Investigations Unit which wants to retain the right to prevent onward dissemination of some papers to relatives on the grounds of national security.
“The UK Government firmly believes that the way to address the past, and provide better outcomes for victims and survivors, is through the legacy bodies in the Stormont House Agreement,” the spokeswoman said.
“We will continue working with the Northern Ireland Executive and the new Irish government to try and establish the necessary consensus to introduce legislation establishing them.”
Sinn Fein president Gerry Adams also called for the classified documents to be opened.
“It is vital that the new government lives up to the need to ensure the utmost pressure is put on the British administration to release their files,” he said.
Brendan Smith, Fianna Fail TD for the Cavan-Monaghan area, said Britain should remove all obstacles to a full investigation into alleged collusion.
“The least the victims and the families of all these atrocities deserve is the truth about who carried out these murderous deeds 42 years ago,” he said.