Rescue efforts are under way after torrential rains and floods washed away buildings and roads, killing at least 64 people in north India, with thousands of pilgrims stranded in the Himalayan state of Uttarakhand, officials have said.
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 on Tuesday.
Local government officials in the state capital Dehradun 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 the AFP news agency 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
"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."
"Certain areas are still unaccessible to us," he added, speaking from a control room in Dehradun which is monitoring rescue and relief missions.
More than 10,000 pilgrims stranded along a mountain pass leading to a Hindu religious site were being evacuated by helicopter after roads to the pilgrimage spot were blocked by landslides.
The army was also working to evacuate thousands from popular locations in Dehradun, Uttarkashi and Rishikesh.
A military statement said five airbases in northern India have been activated to speed up operations.
Pilgrimage trips cancelled
Television footage showed bridges, houses and multi-storey buildings crashing down and being washed away by the swirling waters.
As many as 250,000 people are thought to be in danger. The hilly terrain has made rescue operations difficult.
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.
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 the remote villages.
The Indian Prime Minister Manmohan Singh spoke with officials in Uttarakhand and promised "all assistance in rescue and relief operations" in the the stricken state, the premier's office said in a statement mailed to AFP.
In the neighbouring Himachal Pradesh state, the death toll from rain-related accidents stood at 10, said a state government official from the capital Shimla.
About 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 JM Pathania, a top administrative official of Kinnaur district of the state.
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.
The River Ganges and its tributaries are flowing above the danger mark in several areas in Uttarakhand.