The powerful bomb in a water tanker ripped through a packed bazaar in Hazara town, an area dominated by Shiites on the outskirts of Quetta - capital of oil and gas rich Baluchistan province - at around 6pm local time on Saturday.

"We have recovered more dead bodies from the debris of a collapsed building. The death toll has now risen to 79," senior Quetta police official Wazir Khan Nasir said on Sunday.

Quetta city police chief Zubair Mehmood said the water tanker, which officials said was packed with some 800 kilograms of explosives, was placed near a pillar of a two-storey building, which collapsed in the blast.