Nine confirmed dead after Mumbai building collapses

Rescue workers in Mumbai were searching for up to 20 people feared trapped in a six-storey building that collapsed.

The incident follows two days of torrential rain in India's commercial hub.

Nine people had been confirmed dead, a municipal authority official said. Rescuers estimated more than 16 had been injured and taken to hospital.

"Rescue operations are already underway. We have sent 12 fire brigade vehicles to the spot. Ambulances are also ready to take the victims to the hospital," a fire control room official said.

The collapse is the second in Mumbai in a little over a month.

In July, 17 people were killed when a four-storey building crumbled after undergoing suspected unauthorised renovations.

Police had yet to determine what caused the collapse on Thursday, which was again testing the city's rescue operations after 14 people were killed by floods from heavy monsoon rains earlier in the week.

A police official said nine families were living in the old building, in the Dongri neighbourhood, an area of narrow streets with closely packed buildings, some nearly a century old.

Adjacent buildings were evacuated after the collapse, officials at the site said. The narrow streets made it difficult to bring in excavators, they said.

A large team from the National Disaster Response Force (NDRF) was also involved in the rescue operations.

The building housed a sweet shop warehouse on the ground floor and most families living on the higher floors were in their houses as the collapse happened early in the morning, officials said.

Building collapses are common in India during the monsoon season, which is June to September. High demand and lax regulations encourage some builders to use substandard materials or add unauthorised extra floors.