Mr Adams, whose importance and influence is being reassessed by the governments in London and Dublin, insisted Sinn Fein was not responsible for the bomb and was determined to pursue ultimate peace.
Seeking to keep the door to the peace talks ajar, he argued "it is sheer folly to return to the old agenda of excluding Sinn Fein and seeking to isolate republicans".
His comments came as police hunting the bombers tried to trace a taxi driver who delivered cash to pay for the van which carried the massive bomb into Manchester city centre. They are also viewing tapes from over 40 closed circuit television sources in and around the city centre to see if the bomber has been caught on video.
With the entire Northern Ireland and Anglo-Irish agenda altered by the bombing, public debate centred yesterday on the issue of whether Sinn Fein could now be allowed into talks, and on the question of whether the idea of a peace process including republicans should be dropped.
Last night John Major and John Bruton, the Irish Prime Minister, discussed joint action to try to keep the peace talks alive, and agreed the two governments should keep up a united front against the IRA.
Northern Ireland ministers ordered the Royal Ulster Constabulary to enforce the provisions of anti-terrorist legislation which could enable the security forces to detain suspects for up to seven days without charge. "We are not going to bring in internment. But we are going to do everything within the law. There is going to be a crackdown," said one senior ministerial source.
In Dublin, ministers meet today to appraise their approach of wooing republicans in the light of the bombing. A Cabinet meeting will receive a comprehensive security briefing before assessing whether all hope of a resumed IRA ceasefire has evaporated.
Mr Adams comments came just before an ominous statement from the Ulster Freedom Fighters, a name used by the paramilitary Ulster Defence Association, saying they believed the IRA was planning an imminent resumption of violence in Northern Ireland.
The UFF said it had alerted its personnel to be prepared for all eventualities. On a calmer note, however, the statement went on to say that the UFF remained committed to the peace process and called on the IRA to reinstate its ceasefire.
In a reaction to this, Ulster Unionist leader David Trimble said he too believed the IRA was planning a resumption of violence in Northern Ireland, but appealed to loyalists not to become involved. "The IRA are trying to give themselves a spurious excuse by provoking loyalists into action. I hope loyalists will not fall into that trap."
Another warning came from Gary McMichael, leader of the Ulster Democratic Party, which is closely aligned with the UDA. "I think it would be wrong of me to be anything but honest - we are at a critical point in the peace process. We must use all power and responsibility and all influence that we have to try to ensure that there is not a degeneration into full scale conflict," he said.
British ministers are pressing the White House to take tougher action against Sinn Fein and make clear that Mr Adams will not be granted a visa to visit the US until the ceasefire is restored. "Clinton's people could do more than just saying they will look at it if Adams applies. They could go much further and send the right signals to the IRA," said a ministerial source.
In a message to the people of Manchester yesterday, Mr Major said: "The terrorists must see that their guns and their bombs will not deflect a democratic society from the determined pursuit of a lasting peace in Northern Ireland."
Michael Howard, the Home Secretary, last night described the bomb attack as "a despicable act". He said no effort would be spared by police to catch those responsible.
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