MUMBAI • Fire tore through a sweet shop in the Indian city of Mumbai before dawn yesterday, sparking a building collapse which killed 12 sleeping workers, the authorities said.

Four people were injured while some others saved their lives by scrambling out seconds before the collapse of the building in the Saki Naka area, Agence France-Presse (AFP) reported.

Fire crews and other rescuers saved many trapped workers but 12 died of their injuries, said Mr Tanaji Kamble, spokesman for Mumbai's disaster management cell. "The casualties could have been much higher but luckily some workers managed to escape before the building collapsed," Mr Kamble added.

The authorities are looking into the cause of the blaze in the store in India's financial capital.

"The fire started on the ground floor and the people inside were sleeping in the loft," chief fire officer P. S. Rahangdale of the Mumbai Fire Brigade was quoted as saying by The Hindu newspaper.

"They got trapped in the... structure due to the intense heat and smoke, and the loft subsequently collapsed."

The paper said the fire, which started around 4am, is believed to have been caused by a short circuit.

"The electric wiring and installation, and a huge stock of eatables, furniture and sheets had caught fire," said an unnamed fire brigade official quoted by the Hindustan Times newspaper.

The blaze, however, did not spread beyond the 9m by 18m ground-floor structure, and was doused in 30 minutes by firemen.

Building disasters are common in Mumbai, especially during the monsoon season from late June to September. Millions of people live in cramped dilapidated properties because of high rental prices and activists say housing owners and builders often cut corners to save costs, AFP reported.

In August, seven people died after a building collapsed in Mumbai following days of heavy rain.

In July, 17 people died when a four-storey building gave way in the northern suburb of Ghatkopar. And in 2013, 60 people were killed when a residential block came crashing down in one of Mumbai's worst housing disasters.