The Taoiseach, Mr Ahern, the Northern Ireland Secretary, Mr Peter Mandelson, the Ulster Unionist Party security spokesman, Mr Ken Maginnis and the Sinn Fein President, Mr Gerry Adams were among those who condemned the Irvinestown bombing last night.
The Taoiseach said in a statement that those who planted it "refused to acknowledge the will of the overwhelming majority of the people on this island for peace.
"We utterly reject the motives of such people and we must not allow them to thwart the progress we are making in resolving the outstanding issues in the peace process - and we won't!" the statement said.
Mr Mandelson, said: "My immediate thoughts are with the owners and customers of the Mahon Hotel as well as the people of Irvinestown who are the victims of this attack.
"The people of Ireland, north and south, rejected violence once and for all when they overwhelmingly supported the Good Friday agreement. Tonight's attack is not just wrong - it is against the democratically-expressed wishes of the people."
Mr Adams said on RTE last night: "The people involved are not acting in the interests of Irish republicanism. They are not acting in the interests of any real section of the Irish people and they should disband."
The Sinn Fein Minister of Education, Mr Martin McGuinness, also "unequivocally condemned" the attack, last night, and called on the Continuity IRA to disband, saying: "They have no support in our community."
The leader of the Labour Party, Mr Ruairi Quinn, described the attack as a "calculated insult to the wishes of the Irish people. Those who carried out the attack are beneath contempt."
A spokesman for the Northern Ireland Office said: "We obviously condemn any such attack. If we want to move forward we must do so through democratic means."
A Downing Street spokesman said: "There will always be people who try to undermine the peace process. We will do what we can to make sure they do not succeed."
The Fermanagh-South Tyrone Ulster Unionist Party MP, Mr Ken Maginnis, said the attack by the CIRA had been feared for some time.
He told the news agency PA: "I have had discussions quite recently with the Chief Constable about this very likelihood. It vindicates those of us who believed that democracy cannot reconcile organisations with illegal weapons in executive authority."
The RUC Chief Constable, Sir Ronnie Flanagan, said yesterday the Provisional IRA posed no threat at present but that the two dissident groups did.
In an interview with the northern edition of the Sunday World, he said: "We have these dissident groups and of particular concern is the so-called Real IRA and Continuity IRA . . . they continue to pose a threat."
Mr Sean Farren, an SDLP minister in the Northern Executive, said the bomb was deliberately timed to heighten community tensions.
He told PA: "It is madness. It has no purpose but to drive people apart. Given the looming crisis, the attack was clearly calculated to exploit the situation."
Mr Ian Paisley jnr blamed the IRA for the attack. He told PA: "It was a clear demonstration by the Provisionals of their threat to return to war and squeeze more concessions from the British Government later this week.
"Nobody should be fooled. It was their handiwork, to prove that not only can they carry out a bomb in Fermanagh but London as well."