Ten people were killed, twelve injured and over 60 feared trapped when a six-storied residential building partially collapsed in a northwest suburb of Mumbai on Wednesday.

A portion of the 20-year-old Laxmi Chhaya building at the Babhai Naka in suburban Borivali collapsed at around 5.30 pm resulting in the casualties, the police said.

The deceased include three men, six women and a girl while four of the injured have been discharged after being administered primary treatment, they said.

Mayor of Mumbai Shubha Raul said 60 more are feared to be trapped in the debris and added that prima facie, the civic body suspects that the building would have collapsed due to some major structural changes carried out by a jewellery shop on the ground floor.

Deputy Chief Minister of Maharashtra R R Patil, who visited the spot, has ordered an enquiry into the collapse and questioned why did not the building figure in the list of endangered buildings in the city.

He has also assured relief from the state government to the kin of the deceased and the injured persons.

The police said that 12 of the total 24 residential apartments and around seven commercial establishments on the ground floor have collapsed.

Shopkeepers, customers and some residents are suspected to be amongst those trapped, police said without giving the number of those trapped.

Eyewitnesses said some patients who had come to see a doctor located in the building were also among those trapped.

The entire area has been cordoned off and senior officials, including the Fire Brigade chief and the Police Commissioner are on the spot monitoring rescue work.

The civic body spokesperson added that two earthmovers and two dumpers have been employed at the site for the rescue work while the fire brigade said that over a dozen fire engines and paramedic personnel had reached the spot.

Raul said residents of the building had also "complained" to the managing body about the renovation carried out by the jeweller.

Rescue efforts on the site are expected to continue through the night, police said.