KARACHI -- Two suicide attackers detonated a bomb at an outdoor Sunni Muslim prayer service yesterday, killing at least 55 people and wounding dozens. Angry crowds torched cars and hurled rocks at police, who fired warning shots into the air.
The bomb exploded near leaders of the Sunni Tehrik religious group, which had helped organize the service at a central Karachi park, said the police chief, Niaz Siddiqui. The leaders were sitting near a stage erected in front of thousands of Sunnis marking the birth of the Prophet Mohammed.
Several leaders were killed.
''The bomber used about 5 kilograms [11 pounds] of explosives obtained locally," Siddiqui said yesterday.
Today, a spokesman for the government of southern Sindh province, of which Karachi is the capital, said that 57 people, including two bombers, had been killed in the bombing and that about 100 had been wounded.
The spokesman, Salahuddin Haider, said that two headless bodies were found in the aftermath, and that this indicated two attackers.
The president, General Pervez Musharraf, condemned the attack and ordered increased security at religious sites, adding that the culprits ''will not go unpunished," according to a statement issued on Pakistan's state-run news agency.
It was not immediately clear who was responsible for the bombing, one of the deadliest ever in Pakistan. Attacks in the past have been linked to simmering Shi'ite-Sunni Muslim tensions.
Mayhem erupted after the explosion. Scores of men wearing white, blood-splattered robes clambered onto the stage to assist victims.
''I saw body parts everywhere," Mohammed Asif said. ''I saw people collecting body parts and putting them into ambulances."
Crowds of people ran in different directions, many aiding and carrying the wounded to dozens of ambulances. Some waved green flags bearing Koran scripture. Others wept openly. A cloud of white smoke hung above the park.
Police officers fired into the air to disperse crowds.
Soon after the bombing, violence erupted in nearby areas as groups of youths burned a gas station, buses, and several cars. Another mob pelted security forces with stones.
Television footage inside several Karachi hospitals showed scores of victims being treated in crowded wards. A screaming woman wailed over a person killed in the blast, the body covered by a white sheet on a hospital bed.
A young boy with burns on his face said he was praying in the park when the blast went off.
''I saw fire and smoke after the big explosion," the unidentified boy told Geo television.
Two Sunni Muslim clerics were among the dead: Akram Qadri, a leader of the Tehrik group, and Karachi Sheik Hanif Billu, government and hospital officials said.
Karachi has been the scene of several bombings and other attacks since Pakistan became a key US ally after the Sept. 11 attacks.