Ten people were killed and up to 25 were feared trapped after a three-storey residential building collapsed before dawn on Monday in western India, officials said.
The accident in the city of Bhiwandi, which neighbours India's financial capital Mumbai, occurred around 3:40 am (2210 GMT Sunday), local authorities said.
"Ten people have died, we have rescued 11 people alive," an official at the Thane city authority, which oversees Bhiwandi, told AFP.
More than 40 emergency workers had arrived at the scene, the official said, including a team of 30 rescuers from the National Disaster Response Force (NDRF).
NDRF director general Satya Narayan Pradhan tweeted that teams armed with specialised equipment and sniffer dogs were trying to rescue some "20-25 feared trapped".
Images broadcast on the NDRF's official Twitter page showed emergency workers combing through concrete and brick rubble with electrical wires hanging over their heads.
The cause of the accident was not immediately clear, but building collapses are common during India's June-September monsoon, with old and rickety structures buckling after days of non-stop rain.