MR Gerry Adams, in his first reaction to the bombing and IRA statement, said, the party's peace strategy remained the "main function" of Sinn Fein. He denounced the British government and unionist parties for refusing to enter into all party talks.
The Northern Secretary, Sir Patrick Mayhew, however, was dismissive of the Sinn Fein president's further appeal for calm in the wake of the bombing.
Mr Adams said his response to last night's events was one of sadness.
"My sympathy and thoughts are with those injured. I regret that an unprecedented opportunity for peace has foundered on the refusal of the British government and the unionist leaders to enter into honest dialogue and substantive negotiations.
"I appeal for calm. Sinn Fein's peace strategy remains the main function of our party. It is my personal priority. All those who made genuine efforts to build a peace process must keep our nerve in the face of predictable and hypocritical reaction from public representatives who have done nothing to encourage the risky search for a peace settlement.
"That search must `be redoubled," said Mr Adams Sir Patrick Mayhew said the bombing vindicated the fear that the IRA's refusal to begin decommissioning represented a threat of violence. He said it looked "very unpromisingly" that the IRA statement was genuine.
If the bombing ran counter to Sinn Fein policy then the party should have no difficulty in unequivocally condemning the attack, he added.
