A powerful bomb ripped through a Shiite Muslim mosque in southern Pakistan on Friday, killing at least 49 worshipers and wounding dozens in the deadliest sectarian attack in months in the South Asian nation.
The blast occurred during Friday prayers in the Sindh province city of Shikarpur, hospital and police officials said.
Police officials said at least 170 worshipers had gathered inside the two-story mosque for prayers. Investigators were still determining whether the blast was set off by a suicide bomber or an explosive device planted inside the building.
Abdul Qadoos, a senior police official in Shikarpur, said the blast was so powerful that the roof of the mosque collapsed and several victims were trapped under debris.
Many of the casualties were taken to hospitals in other parts of Sindh as facilities in Shikarpur were overwhelmed by the scope of the disaster.
Local resident Mohammad Jehangir "felt the earth move beneath my feet" as he prayed at another mosque about a mile away, according to the Agence France-Presse news service.
Shiites constitute between 15% and 20% of the population of Pakistan, which is majority Sunni Muslims. Sectarian violence primarily targeting Shiites dropped in 2014 after surging sharply the previous two years, according to the South Asia Terrorism Portal, which studies the issue.
According to the group, 210 Pakistanis were killed in sectarian violence in 2014, less than half the death toll of the year before.
Friday's bombing comes as Pakistan is attempting to implement a national plan to root out terrorism from the country following last month's attack by the Pakistani Taliban on an army-run school in Peshawar that killed more than 130 students.