Sinn Fein president Gerry Adams has said he "regrets" the Birmingham pub bombings which killed 21 people.
Two pubs were destroyed in the 1974 bombings
On the 30th anniversary of the bombs he said: "I certainly regret what happened and I make no bones about that."
Two pubs, the Tavern in the Town and the Mulberry Bush, were destroyed in the attacks in November 1974.
At a memorial service on Sunday to remember those who died the Archbishop of Birmingham urged people to "learn from our bitter past".
Hundreds of people joined survivors at the city's St Philip's Cathedral to remember the victims.
Asked whether the IRA should apologise, Gerry Adams pointed to a statement the IRA made two years ago when it apologised to all civilians killed and injured.
"My recollection very clearly is that the IRA apologised for all the actions it engaged in which civilians were hurt or injured.
"I think the best thing is for us to make sure that these awful events never happen again."
But one survivor said a "genuine" apology was still needed.
Maureen Mitchell told the BBC: "They have got to first admit that they were responsible before they can apologise and I have got to feel that that apology would be genuine."
At the service on Sunday the Roman Catholic Archbishop of Birmingham, the Most Reverend Vincent Nichols, said: "Lives were destroyed and changed that night in a most brutal fashion which no cause could ever justify. The passing of time does not alter that.
Some people still seek a "genuine" apology.
"May ours be a prayer that those who acted in this way may come to a change of heart, acknowledge their deeds and take a step on the road of reconciliation.
"Everyone can make a difference by pledging to make just a small change in your lifestyle.
"May the lord bless us as we try to change, learning from our bitter past and building a better world for tomorrow."
Although the IRA never admitted carrying out the attack, the bombings were blamed on them and led to reprisal attacks on the city's large Irish community.
Six Irish men - Hugh Callaghan, Paddy Hill, Gerard Hunter, Richard McIlkenny, William Power and John Walker - were convicted in 1975 of carrying out the attacks.
But in 1991, the Appeal Court quashed their convictions, bringing to an end one of the UK's most infamous miscarriages of justice.
The Sunday service was led by the city's first Irish-born Lord Mayor, Cllr Mike Nangle.
He said the occasion would be marked by all sections of the community.
"People who have lost their relatives or were injured on that terrible day have to live with what happened every day of the week for the rest of their lives.
"I hope this service to commemorate loved ones will provide them with some small measure of comfort."
Following the service the Archbishop was joined by the Dean of Birmingham, The
Very Reverend Gordon Mursell and the Lord Mayor in laying a wreath in memory of the dead in the Cathedral grounds.
Members of the public gathered round to watch the ceremony which started with
a procession of clergy and choir members from the Cathedral door.