KARACHI, Pakistan - A bomb exploded during an Islamic prayer service at a park in this southern Pakistani city Tuesday, killing at least 40 people and wounding dozens.
An angry mob burned cars and threw stones at police, who fired into the air to disperse the crowds, a witness said.
Initial reports suggested a bomb was planted near the stage in Nishtar Park in Karachi, Pakistan's largest city, for a prayer gathering organized by a Sunni Muslim group to celebrate the birth of Prophet Muhammad, said area police chief Shah Nawaz.
But Interior Minister Aftab Khan Sherpao told Pakistan's private Geo television that authorities were also investigating whether the attack may have been carried out by a suicide bomber.
Sherpao told The Associated Press that at least 40 people were killed. "It is a very unfortunate incident," he said.
Scenes of mass confusion broke out after the explosion in the park, where hundreds of people had gathered for the prayer service.
Scores of men wearing long white, blood-spattered robes clambered onto the stage to assist victims, some apparently dead and others wounded and waving their arms for help. A plume of smoke caused by the blast hung over the stage.
People were seen carrying away bloodied blast victims and placing them into ambulances. Four men carried one victim in what looked like a white sheet soaked with blood. Several bodies were seen lying side-by-side on a strip of dusty ground.
Police officers fired into the air to disperse crowds that massed at the scene. An angry mob burned cars and pelted security forces with stones after the blast, said witness Mohammed Asif.
"I saw body parts everywhere. I saw people collecting body parts and putting them in ambulances," Asif said.
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 a massive blast ripped through the crowd. "I saw fire and smoke after the big explosion," the unidentified boy told Geo television.
Sindh Provincial Interior Minister Raouf Sadiqui said officials were investigating the attack but that "so far we don't have any confirmed information."
Two prominent Sunni Muslim clerics were among the dead, including Akram Qadri, a senior leader of the Sunni Tehrik religious group that organized the prayer service, said Sami Jamali, a doctor at a nearby hospital. Sadiqui said Sheik Hanif Billu also died.
Karachi has been the scene of several bombings and attacks since Pakistan became a key ally of the United States in its war on terror after Sept. 11, 2001.
On March 2, a suicide bomber who was blocked from driving into the U.S. Consulate instead slammed into an American diplomat's car, killing the envoy and three others just days before President Bush visited Pakistan.