At least 35 people were reported to have been killed on Friday after an explosion during prayers at a Shiite mosque in Shikarpur. The small city is in Sindh province, about 500 kilometers (310 miles) north of the port of Karachi. News agency reports of the death toll varied but with dozens of people reportedly injured and searchers hunting frantically through the mosque's rubble, it was feared the number of victims would rise.

"The area is scattered with blood and flesh and it smells of burnt meat, people are screaming at each other... it is chaos," witness Zahid Noon told the news agency AFP.

Witnesses reported that hundreds of people had rushed to the scene to try and dig out victims after part of the mosque's roof collapsed.

Shiite Muslims are a minority in Pakistan making up about a fifth of the population. Extremists from the Sunni Muslim majority have in the past targeted Shiite religious institutions and citizens, because they do not consider them to be true Muslims.

"We are trying to ascertain the nature of the blast," Shikarpur police chief Saqib Ismail Memon said, adding that a bomb disposal squad was examining the scene.

'Islamic State' ally claims responsibility

The Sunni militant group Jundullah has claimed responsibility for the attack.

"Our target was the Shia community (mosque)... They are our enemies," Fahad Marwat, a spokesman for Jundullah, told Reuters news agency. The group has links to the Pakistani Taliban and last year reportedly pledged support to the "Islamic State" extremist Sunni group which has taken over large areas of Syria and Iraq.

Pakistan's government in December ended a moratorium on the death penalty in terror-related cases, set up military courts to try terror suspects and pledged to crack down on militant groups. The measures followed the massacre by Taliban militants of about 150 people, mainly children, at a school in the northwestern city of Peshawar.

se/bw (Reuters, dpa, AP, AFP)