The death toll in the building collapse in Virar area of Palghar district of Maharashtra has risen to 15.
Officials said on Thursday that three more bodies were recovered from the debris overnight.
This four-storey illegal building with about 50 flats collapsed on a nearby vacant house in Vijay Nagar area at around 12:05 am on Tuesday and Wednesday.
According to eyewitnesses, the birthday of a one-year-old girl was being celebrated on the fourth floor when 12 flats in a part of the building suddenly collapsed and many residents and guests were buried under the debris.
Palghar District Collector Dr Indu Rani Jakhar confirmed on Thursday morning that the death toll has risen to 15.
Police have arrested the builder of the building after the Vasai Virar Municipal Corporation (VVMC) filed a complaint.
Two teams from the 5th Battalion of the National Disaster Response Force (NDRF) are carrying out the operation at the site.
Palghar District Collector Indu Rani Jakhar said there is a possibility that more people could still be trapped beneath the debris.
According to District Disaster Management Officer Vivekanand Kadam, the 'chawl' on which the structure collapsed was vacant during the time of the incident.
As a precautionary measure, all nearby chawls have been evacuated and residents shifted to safer locations.
Kadam said that Ramabai Apartment, constructed in 2012, had a total of 50 flats, with the collapsed portion consisting of 12 apartments.
A spokesperson for the VVMC confirmed that the building was illegal.