A powerful bomb explosion at a religious gathering of Sunni Muslims in Pakistan has killed at least 56 people and injured dozens.
The bombing occurred at a public park in the southern city of Karachi, where thousands of Sunni Muslims had gathered to celebrate the birth anniversary of Islam's Prophet Mohammed.
Initial reports suggest the bomb was planted under a stage and went off while the crowed was offering a prayer to mark the end of the ceremony.
Federal Interior Minister Aftab Ahmed Sherpao says that the powerful explosion instantly killed dozens of worshipers.
"There are a number of casualties in this [attack]," he says. "The injured have been taken to [Karachi's] Civil Hospital and Jinnah Post-Graduate Hospital. But we are still waiting for the details."
Witnesses say that scenes of mass confusion broke out after the explosion in the park. Television pictures showed bodies lying on the ground and wounded being taken to hospitals in vans after the explosion.
Police fired into the air to disperse crowds that gathered at the scene. Reports say angry mobs burned cars and pelted security forces with stones after the blast.
There were no immediate claims of responsibility, but sectarian violence between Sunni and minority Shi'ite Muslims has killed hundreds of people in Pakistan in recent years. Early this year, at least 40 people were killed when a suicide bomber attacked a Shi'ite procession in northwestern Pakistan.
Pakistani officials say that security experts are also investigating whether the attack was the work of a suicide bomber.