At least 7 people were killed and another 70 people were injured after a powerful explosion ripped apart a three-storey building in central Dhaka, Bangladeshi officials said, citing a gas pipeline as the likely cause.

Police said the explosion was so forceful that it broke the windows of at least four moving buses, injuring dozens of passengers on board.

Dhaka police chief Shafiqur Rahman said at least seven people were killed in the explosion, though the fire service offered a lower death count of 3. Witnesses told local media the blast had reduced the building - which houses a restaurant, an electronics shop and several other stores - to rubble.