A warning, telephoned to a news agency in Belfast at approximately 2.30pm and passed on to the then Royal Ulster Constabulary, referred to a bomb at Omagh Courthouse, roughly 400 meters from where the bomb exploded. Many of those killed and injured had been moved from the vicinity of the courthouse and into the area where the bomb was situated. At 3.10 pm the car bomb exploded in Omagh. The bomb had been planted close to the junction of Market Street and the Dublin Road in the centre of the town.
Those at the scene desperately tried to find and help the injured. Within minutes the local Tyrone County hospital was receiving casualties. Reports at the scene said eight to ten people had been killed. The RUC said that there were a large number of casualties but would not confirm any fatalities. Shortly after 6pm the RUC said up to 100 casualties had been taken to Tyrone County Hospital in two buses.
Those who had been injured were initially taken to two local hospitals, the Tyrone County Hospital and the Erne Hospital in Enniskillen. Buses and cars were used to ferry the injured to the hospitals. Many of the more badly injured were then flown or driven to other hospitals in Northern Ireland including the Royal Victoria Hospital in Belfast and Altnagelvin Hospital in Derry. Medical staff described the situation as "battlefield conditions".
A statement on behalf of the Queen expressed her shock at the "appalling crime" and asked for "my heartfelt sympathy" to be passed on to the bereaved families, injured and others who had suffered.
At 10.45pm the police issued a press release. The death toll was now 25 exceeding any previous terrorist attack in Northern Ireland. The sub-divisional commander spoke of his heartbreak at the horrific casualties and praised the extraordinary efforts of the emergency services and ordinary people caught up in the tragedy.
21 died at the scene, hundreds more were injured and of those injured 11 were described as being critical. First reports said that 113 had been detained in hospital. The news of the tragedy started spreading around the world and the numbers of killed and injured rose with every report. Cardinal Basil Hume, Catholic Archbishop of Westminster asked for prayers for everyone affected by "a crime against humanity".