In his first condemnation of a republican paramilitary action, the Sinn Fein president, Mr Gerry Adams, called on those who planted the Omagh bomb to admit responsibility immediately and then cease all such activity.
His colleague, Mr Martin McGuinness, called the bombing "indefensible", said he was appalled and disgusted at the attack and that it was designed to wreck the peace process. He too called on the group responsible to stop its attacks.
In a statement hours after the bomb detonated on Saturday, Mr Adams said simply: "I am totally horrified by this action. I condemn it without any equivocation whatsoever." Mr Adams broke off a holiday to return to Northern Ireland and visited the scene of the explosion yesterday.
In a further statement from Omagh yesterday he called for a meeting between the leaders of all the political parties to discuss the crisis. His statement in full said:
"Let me first of all express my heartfelt condolences to the bereaved families and my sympathy to those recovering in hospitals. Like many other people I am shocked at the enormous loss of life here in Omagh. This is a tragedy for all the people of Ireland but particularly for the people of Tyrone.
"I want to reiterate my words of condemnation. I hope that those who planted this bomb understand the enormity of their actions. They should admit responsibility for it without delay and they should stop their activity immediately.
"This is not a time for anyone to be playing politics with this tragedy. There is now an urgent need for Mr Trimble and Mr Mallon to call together the leaders of all the political parties to discuss this crisis.
"I am appealing to people even in the midst of this awful event not to lose hope, not to despair. There is a path out of this dark tunnel. I will work with others, as we have been all along, to secure the peace that all of us want."
Mr McGuinness's statement, issued on Saturday afternoon, said: "I am appalled and disgusted at what has happened in Omagh today. It was an indefensible action.
"My thoughts are with the families of those who were killed and of course with the many people who were injured. I offer my condolences to the bereaved families and wish a speedy recovery to the injured.
"This appalling act was carried out by those opposed to the peace process. It is designed to wreck the process and everyone should work to ensure the peace process continues. I call on whatever group was responsible to stop immediately.
"Those responsible are aligning themselves with the forces opposed to a democratic settlement of the conflict here."