Hours later, a car bomb containing more than 600 pounds of explosives forced the evacuation of hundreds of people from shops in Lisburn, a mostly Protestant town southwest of Belfast.
The unclaimed bomb, which was safely defused, was the first such attack in Northern Ireland since early February, when opponents of the IRA's 1997 truce bombed two other predominantly Protestant towns.
The IRA called the April 10 accord among the British and Irish governments and eight parties, including Sinn Fein, "significant."
But the outlawed group rejected the section requiring Northern Ireland's rival paramilitary groups to "decommission" weaponry, starting in June and finishing within two years.
"Let us make it clear there will be no decommissioning by the IRA," the seven-member command said Thursday in the movement's weekly newspaper, Republican News.
Sinn Fein leader Gerry Adams, a reputed former IRA commander, called the statement balanced. "People need to calm down. What did people expect the IRA to say?" Adams said.
But British Prime Minister Tony Blair and his governor in Northern Ireland, Mo Mowlam, insisted IRA disarmament was an essential part of the accord.
"It's got to be absolutely clear that people who are going to serve in the government of Northern Ireland have got to have given up violence for good," Blair said in Manchester, a northwest England city devastated by an IRA bomb two years ago.
The crisis came as former U.S. Sen. George Mitchell, who guided 22 months of negotiations to the accord, returned to Belfast to accept an award from the Northern Ireland Chamber of Commerce.
Mitchell emphasized that he expects the IRA to honor the part of the agreement specifying that it and the north's pro-British paramilitary groups should disarm by May 2000.
"I believe strongly that there must be the total decommissioning of all paramilitary arms," Mitchell told Ulster Television, adding that it "will eventually happen."
On Friday in Dublin, Mitchell will have lunch with Irish Prime Minister Bertie Ahern and receive an honorary doctorate from Trinity College.
The unsigned agreement, which must be approved in public referendums May 22 in Northern Ireland and the Irish Republic, would create a new 108-seat Assembly directed by a multi-party Executive.
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