MUMBAI (AFP) - At least 13 people were killed in India when a three-storey residential building collapsed before dawn on Monday (Sept 21), media reports said, while a disaster agency official said up to 25 people were believed to be trapped in the ruins.

Local residents cheered as emergency workers from the National Disaster Response Force (NDRF) pulled 20 survivors - including two boys aged four and seven - from the rubble of the building in Bhiwandi, on the outskirts of Mumbai.

"The total number of deaths... is 13," NDRF commandant Ithape Pandit told AFP.

NDRF director general Satya Narayan Pradhan tweeted that specialist teams and sniffer dogs were trying to rescue another "20-25 feared trapped".

An official at the Thane city authority, which oversees Bhiwandi, told AFP that more than 40 emergency workers were helping search for survivors.

Images broadcast on the NDRF's official Twitter feed showed emergency workers combing through concrete and brick rubble with electrical wires hanging over their heads.

The cause of the pre-dawn 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.