A suicide bomb explosion at a religious gathering in Pakistan's southern port city of Karachi has killed at least 45 people and wounded more than 50.
Karachi's police chief Niaz Siddiqui says the suicide bomber used five kilograms of locally obtained explosives.
The bomb was exploded near the main stage during evening prayers at the Nishtar public park, where thousands of Sunni Muslims were celebrating the Prophet Muhammad's birthday anniversary. The dead included three prominent Sunni leaders.
There has been no claim of responsibility for the blast.
The explosion triggered a panic in the crowd. Some people threw rocks at government vehicles when officials came to the scene.
Later, angry mobs rampaged through several parts of the city, burning motorcycles and other vehicles. Police fired tear gas to disperse the crowds.
Karachi has often been the scene of sectarian violence between Sunni and minority Shi'ite Muslims.