Helicopters airlifted stranded families from rooftops and dam gates were thrown open as incessant torrential rain brought fresh havoc on Thursday to the Indian state of Kerala where about 100 people are feared dead.
Hundreds of extra troops were deployed in the southern state, as the government issued a "red alert" over the region's worst floods in decades.
State authorities said the confirmed death toll was 72 but officials and media reports said up to 30 more people were feared dead on Thursday in landslides and as rivers burst their banks, flooding scores of villages.
At least eight people were reported dead and 15 others, including a three-month-old infant, were trapped inside three houses hit by a landslide near an irrigation dam in Malappuram district, the Hindu
Authorities said many people were trapped inside their houses. More than 60,000 people have sought refuge in relief camps.
"At least 6,500 people are stranded in different parts of Kerala and the situation in three districts is particularly grim," a Kerala state disaster management official told AFP.
Kerala, famed for its pristine palm-lined beaches and tea plantations, is battered by the monsoon every year but this year's damage has been particularly severe. Floods have also caused havoc in other states, including Karnataka and Madhya Pradesh.
Some 540 army, navy and air forces reinforcements were sent to Kerala on Thursday to join the rescue effort.
The army said it had rescued scores of people with helicopters sent to the region. Defence forces and government boats were also used in an increasingly desperate rescue operation.
Authorities appealed for victims to stand in open fields or on rooftops away from trees so helicopters were not damaged during rescue efforts.
People could be seen paddling lifeboats provided by the military, while in some areas families commandeered local wooden boats to ferry themselves to safety.
Army helicopters rescued families but also dropped food packets and drinking water to some of the worst-affected districts.
The government says 10,000 kilometres of Kerala roads have been destroyed or damaged and hundreds of homes lost.
It has ordered the opening of gates at 34 dams and reservoirs where water levels had reached danger levels.
Cars and livestock washed away in the floods were seen on Indian television, and men and women wading through chest-high waters that had gushed into their homes.
Many used social media to send rooftop distress calls, some with video.
Greeta Mathew pleaded for help for her family in a Twitter message.
"Anybody reading this,PLZ HELP. My relatives are stuck on the upper floor of house with an 8 months pregnant lady, in Edayaranmula, Pathanamthitta dist. All rescue control rooms' numbers busy. No rescue team reached yet. No contact with family since last evening," she said.
North and central Kerala has been worst hit by the floods but all 14 of the state's districts have been put on alert as heavy rain is predicted for several days.
In the main city of Kochi, the international airport was closed until at least Saturday because of flooding. Departures were cancelled while incoming flights have been diverted to other airports in India.
All public transport has been stopped with many buses left abandoned in the road.
Elsewhere, eight people were swept away on Wednesday after a sudden water surge hit a popular picnic in Madhya Pradesh state. Another 45 stranded were rescued on Thursday by police.
Prime Minister Narendra Modi said on Thursday on Twitter that he has ordered the defence ministry "to further step up the rescue and relief operations across the state. Praying for the safety and well-being of the people of Kerala".Last updated: August 16 2018 02:59 PM