A dam burst its banks near Jakarta, sending waves of muddy water laden with debris crashing into a suburb of the Indonesian capital.
The flooding swamped hundreds of homes in the Tangerang district in the middle of the night, catching residents unaware as they slept.
Telephone lines were toppled and
cars swept along for hundreds of metres.
At least 50 bodies have been pulled from the wreckage but rescuers fear the death toll will rise.
Relatives and friends have been gathering at a make-shift morgue in the city to identify and grieve for lost loved ones.
Soldiers have joined the large-scale operation to find bodies and survivors still trapped in their homes.
Rescue workers are wading through deep water and using rubber rafts, but have been hampered by thick mud.
The cause of the burst is unclear, but officials said the Situ Gintung lake behind the dam became overloaded after heavy rain.