Paramilitary soldiers on Wednesday recovered 20 bodies from a steep hillside in northern India where a helicopter crashed while on a mission to rescue people stranded in monsoon floods, the country's air force chief said.

The helicopter crashed late Tuesday when its rotor blades hit the hillside while returning with survivors of flooding and landslides that have killed more than 1,000 people and washed away thousands of homes, roads and bridges since mid-June in the Himalayan state of Uttarakhand.

Soldiers using ropes reached the crash site early Wednesday and found the bodies of 20 people, including five air force crew members, Air Chief Marshal N.A.K. Browne told reporters.

The helicopter's cockpit voice recorder was recovered and an inquiry has been ordered to determine the cause of the crash, Browne said.

Some 45 aircraft have been used in rescue and relief operations, but bad weather has dogged the efforts since Sunday, with intermittent rain and dense fog hanging over the mountains.

Troops on Wednesday were trying to rescue about 5,000 people who remained stranded in the towns of Badrinath and Harsil 10 days after torrential rains triggered the flooding and landslides in Uttarakhand.

Browne visited the hill town of Gauchar, where the air force has mounted its relief and rescue operations. He assured flood survivors that helicopters would rescue everyone stranded in Uttarakhand despite the bad weather and poor visibility.

Hundreds of thousands of Hindus make the Char Dham Yatra pilgrimage to four temple towns in Uttarakhand each year, usually returning home before monsoon rains in July make the mountainous area much more treacherous, but unprecedented heavy rains fell around mid-June this year and caught many by surprise.

About 92,000 people from hundreds of villages and towns hit by the floods have been rescued. Landslides and floods flattened entire towns, roads were washed away and communication links snapped, cutting off many people and necessitating air rescues.