RISHIKESH, India : Torrential rains washed away hundreds of homes and roads, leaving at least 64 people dead and thousands stranded, after the annual monsoon hit northern India earlier than expected, officials said Tuesday.

The Indian Air Force scrambled a dozen helicopters to reinforce a military-backed rescue mission in the worst-hit state of Uttarakhand, a spokesman said. Local govt officials said they were overwhelmed by the scale of the disaster.

"So far, we have found 54 bodies and 17 others are still missing," top disaster management official Piush Rautela told AFP by telephone. "The situation is really very bad out there. More than 600 buildings have toppled or been swept away and there are 75,000 people including pilgrims stranded at various places," he said, adding that military helicopters were rushing to rescue those stranded in water-logged areas.

"Certain areas are still unaccessible to us," Rautela said from a control room in Dehradun which is monitoring rescue and relief missions.

"Indian air force helicopters carried out missions to airlift men, equipment, relief material medical aid," said a statement from the military.

Five airbases in northern India have been activated to speed up operations, it added.

Television footage showed bridges, houses and multi-storey buildings crashing down and being washed away by the swirling waters. A giant statue of Lord Shiva could be seen submerged up to its head in the tourist hub of Rishikesh in Uttarakhand.

Rising water levels in some towns have also swept away cars, earthmoving equipment and even a parked helicopter, as a result of the surprise rains which began lashing the region on Saturday.

Roads in many areas have been destroyed, leaving hundreds of pilgrims stranded on their way to visit shrines in remote areas.

Authorities have cancelled pilgrimage trips, fearing further rains and landslides in the state, often referred to as the "Land of the Gods" because of its many Hindu temples and Hindu religious sites.

Wildlife, including deer, could be seen struggling for safety against the tide.

"Right now our priority is to save as many lives as possible and the scale of destruction will be assessed later," Routela said from Dehradun.

The state government was also readying food parcels and drinking water to be dropped by helicopters to remote villages.

In neighbouring Himachal Pradesh state, the death toll from rain-related accidents stood at 10, a state government official said from the capital Shimla.

Around 1,500 people, including 150 foreign holiday-makers, were stranded in the state which is a popular tourist destination, the official added

Efforts were under way to try to reopen the major roads to rescue those cut off by the rains, said J. M. Pathania, a top administrative official of Kinnaur district of Himachal Pradesh.

The monsoon, which India's farming sector depends on, covers the subcontinent from June to September, usually bringing some flooding.

But the heavy rains arrived early this year, catching many by surprise. The country has received 68 percent more rain than normal for this time of year, data from the India Meteorological Department shows.

Two hydropower stations that supply the region have also been shut down as a safety measure.

Over the border in Nepal, at least 12 people have been killed in landslides triggered by monsoon rain over the last three days, officials said.

Seven members of the same family, including five children, were killed after a landslide buried their home in a remote village in northwestern Nepal, Prakash Gharti Magar, a local police officer told AFP.