The officials said that twelve persons, including a mother-daughter duo, were killed and six others seriously injured after a portion of an unauthorised four-storey building collapsed on an adjacent vacant tenement at Virar in Maharashtra's Palghar district on Wednesday, reported news agency PTI.

While six bodies were retrieved from under the debris, six others died during treatment at various hospitals.

The operation to remove rubble at the crash site has been going on even after more than 20 hours have passed since the rear portion of Ramabai Apartment collapsed at 12.05 am, reported PTI.