KOCHI, INDIA (AFP) - The official death toll from major floods in India's tourist hot spot of Kerala hit 86 on Thursday (Aug 16) with media reporting even higher numbers amid warnings of more torrential rainfall.

"At least 21 people have died today. The official toll is now 86," a Kerala state spokesman.

With a major rescue operation launched to help thousands of people trapped by the floods, Kerala's Chief Minister Pinarayi Vijayan said the state now faces an "extremely grave" crisis.

It was reported earlier helicopters airlifted stranded families from rooftops and dam gates were thrown open as incessant torrential rain brought fresh havoc.

Hundreds of extra troops were deployed in the southern state, a major tourist hot spot, as the government issued a "red alert" over the region's worst floods in decades.