They both made it clear the bombing had made it more difficult for Sinn Fein to be admitted to talks.
Evidence of a hardening of opinion came yesterday from the Taoiseach, John Bruton, who criticised Sinn Fein for being "struck mute" after the bombing, and for refusing to condemn the recent killing of Garda detective in Limerick.
Mr Bruton said: "What is needed now is an unconditional and irrevocable ceasefire. There can be no going back this time, no looking back over the shoulder to the option of violence if politics doesn't go their way. This time they must come irrevocably into the political process."
Andrew Hunter, the chairman of the Tory backbench Northern Ireland committee, said the bombing made Sinn Fein's exclusion from the talks "absolute" for the forseeable future. "I would not be at all surprised if there was not some ceasefire statement during the next few days that would throw confusion and sow dissent among the negotiators."
Michael Howard, the Home Secretary, warned: "No one is going to be taken in. You can't have a situation in which there's a bomb in Manchester on Saturday and the announcement of a ceasefire on Monday and people allowed back into talks on Tuesday. The real world isn't like that."
Some Tory MPs warned that the IRA should begin decommissioning weapons before Sinn Fein is admitted, a view not shared by the governments. There were Tory calls for internment of the "Godfathers" of the IRA, but British ministers said it was a "last resort".
The security forces will also be watching for any sign of possible loyalist retaliation, although David Ervine of the Progressive Unionist party, which is close to the paramilitary Ulster Volunteer Force, said he believed the loyalist ceasefires would hold.
The Irish government will tomorrow review its continuing contacts with Sinn Fein in the wake of the bombing and the killing of the Garda special branch officer in Adare. It is unlikely that the Irish government will break off contact with Sinn Fein, according to highly placed Irish sources, but the review could prove historic.
Both acts by the IRA were condemned yesterday by Mr Bruton and Dick Spring, the Irish Foreign Minister, but the murder of the Garda officer has shocked Dublin. Mr Spring said the killing and the Manchester bombing may mean the leadership of the IRA has split.
"The Adare killing was carried out by a breakaway group from the IRA. That leaves us facing a new difficulty. We always felt we were dealing with a leadership, people who were trying to bring the IRA into democratic politics. The situation could be very different, that we don't know who we are dealing with," Mr Spring said on BBC's Breakfast with Frost.
British ministers believe the only hope for peace now is that the IRA's bombing of Manchester will alienate the nationalists who voted for Sinn Fein in the Northern Ireland elections. Mr Bruton said the voters had been "betrayed" by the IRA.
David Trimble, leader of the Ulster Unionists, said the attack meant his party would keep demands for an IRA weapons surrender as top of their agenda in talks that enter their second week in Belfast today.
"This explosion looks like the work of the IRA. It is the work of a few fanatics and ... causes absolute revulsion in Ireland as it does here."
"This is a time for everyone committed to the objective of lasting peace in Ireland to dig deep and apply ourselves with greater determination to restore the peace process."
"This is a slap in the face to people who've been trying, against perhaps their better instincts, to give Sinn Fein a chance to show that they could persuade the IRA to reinstate the ceasefire."
"Acts of this nature create terrible suffering for the victims and shock for everyone."
The Rev Ian Paisley
"This is a devilish action ... If that is the attitude of the people who want to be at the democratic negotiating table, I would say they have no place at that table."
Mr Adams and Mr McGuinness were members of Sinn Fein/IRA, he said, and that "while they are part of that organisation they have to accept responsibility for what their organisation does".Reuse content