The death toll from monsoon flooding and landslides in mountainous northern India rose to nearly 600 on Friday with rescuers finding bodies in the Ganges and in the muddy, broken earth, officials said.

The air force dropped paratroopers, food and medicine for people trapped in up to 100 towns and villages cut off since Sunday in the Himalayan state of Uttarakhand where thousands of people are stranded, many of them Hindu pilgrims who were visiting four shrines in the area.

The Uttarakhand state chief minister, Vijay Bahuguna, told CNN-IBN television channel on Friday that 556 bodies had been seen buried deep in mud and the army was trying to recover them. Rescuers also found 40 bodies floating in the Ganges near the pilgrimage site of Haridwar, said Rajiv Swaroop, a police officer.

Rakesh Sharma, another state official, said on Thursday that the death toll might reach the thousands, but the exact figure would not be known until the entire region had been checked.

Sushilkumar Shinde, the federal home minister, told reporters in Delhi that 34,000 people had been evacuated so far and 50,000 more were stranded in the region. Roads and bridges were washed away by the floods or blocked by debris.

A spokesman for Uttarakhand, Amit Chandola, said the rescue operation was centred on evacuating nearly 27,000 people trapped in the worst-hit Kedarnath temple area, one of the holiest Hindu sites dedicated to the god Shiva, located high in the Garhwal Himalayan range. The temple escaped major damage, but debris covered the area around it and television images showed the bodies of pilgrims strewn around the area.

Soldiers and other workers reopened dozens of roads by building makeshift bridges, accelerating the evacuation, Chandola said. More than 2,000 vehicles carrying stranded Hindu pilgrims had moved out of the area since late on Thursday and thousands of soldiers were continuing efforts to reach the worst-hit towns and villages, he said.

Thirty-six air force helicopters have been ferrying rescue workers, doctors, equipment, food and medicine to Kedarnath, the town closest to many of those stranded, said Priya Joshi, an air force spokeswoman. Seven aircraft carried paratroopers and fuel to the region.

Hundreds of people looking for relatives demonstrated in Dehradun, the Uttarakhand state capital, where flood survivors were taken by helicopter. They complained the government was taking too long to evacuate the survivors, with helicopters bringing in four to five people at a time.

Jasveer Kaur, a 50-year-old housewife, said she and her family survived by taking shelter in a Sikh shrine, which withstood the flood, located in Govind Dham.

"There was destruction all around," said Kaur after she was evacuated by an air force helicopter. "It was a nightmare."

Google has launched an application, Person Finder, to help trace missing people in Uttarakhand. The version is available in both Hindi and English versions.

The annual monsoon rains sustain India's agriculture but also cause flooding that claims hune numbers of lives and damages property. The neighbouring Uttar Pradesh state said 17 flood-related deaths had occurred there since the heavy rains on Sunday.