Police made five arrests at dawn Monday in connection with the car bomb that killed 28 people and shattered hundreds of lives as it ripped through this religiously mixed town in Northern Ireland.

The five were arrested in two villages north and southeast of Omagh and taken to the main police center in Belfast, 70 miles to the east. Under Northern Ireland's anti-terrorist law, they could be questioned for up to a week before being charged or released.Francis Mackey, leader of a group under suspicion in the bombing, Monday denied the organization was to blame and said his 19-year-old son Shane was one of those arrested. Mackey is chairman of the 32 County Sovereignty Committee, which denies allegations it is affiliated with the "Real IRA," a group of IRA dissidents trying to wreck the province's April peace agreement.

British Prime Minister Tony Blair and his Irish counterpart, Bertie Ahern, emerged Sunday from an hourlong meeting in Belfast vowing to work together to hunt down the bombers - believed to belong to a renegade Irish Republican Army offshoot opposed to April's peace agreement.

"The purpose of that bombing was to destroy the work, destroy the hope and the agreement we built up," Blair said. "Our determination has got to be that these people will never win, and that democracy will triumph over evil."

Meanwhile, a bomb threat Monday at Stormont, the center of British administration for Northern Ireland in east Belfast, caused the evacuation of staff. No injuries were reported and no bomb was found.

Each of the 2,000 residents of Omagh seemed to have a story to tell about Saturday's bombing, offered in flat tones of disbelief: a school chum who won't be in class next month; a father and son who no longer will enliven a neighborhood; a shopkeeper who never again will greet customers with a ready smile.

"I don't understand why I'm living," said Jim Sharkey, who was knocked off his feet at his newsstand on bustling Market Street when the 500-pound car bomb exploded in the worst terrorist strike in Northern Ireland's history.

"How does this town deal with this?" asked the Rev. Michael Keaveny of Omagh's Sacred Heart Catholic Church, outside the makeshift headquarters where the dead, wounded and missing are being tracked.

The town's Market Street, still a scene of destruction, remained sealed off Monday. A mangled baby carriage was parked amid the rubble of a collapsing storefront, half-eaten meals were abandoned on the tables of one cafe, diapers were scattered pell-mell in the road.

Three generations of one family were killed: Avril Monaghan, 30, her 18-month-old daughter Maura and her mother Mary Grimes, 65, who had been visiting from nearby towns to shop on Market Street. Monaghan was pregnant with twins.

A 12-year-old boy from Madrid who was visiting Ireland to learn English died, as did his female teacher twice his age. The two Spaniards had decided at the last minute to put off visiting a historic park to do some shopping. Ten Spaniards were injured in the blasts.

Spain's deputy prime minister, Francisco Alvarez-Cascos, flew to Northern Ireland Monday to be with the victims and their relatives.

Also killed was 39-year-old Philomena Skelton, who had been seeking a school uniform for her youngest daughter.