"The desert looks like a sea. There is no place where one can walk," Captain Saurabh Modi, an army officer who is involved in relief operations in Barmer, told Reuters by telephone.

Hundreds of people marooned on sand dunes, surrounded by over 15 feet (5 metre) deep pools of water, were being rescued by military helicopters and motorised navy dinghies.

Most of the deaths in Rajasthan in the week-long flooding were caused by drowning and house collapses.

"Several bodies are being fished out from the swirling waters," Rajasthan Relief Secretary R.K. Meena said.

A layer of gypsum below the sandy surface is preventing brownish flood waters from seeping into the ground in the region, slowing down relief efforts. Gypsum is a mineral used in the building industry.

"If the flood water does not drain, we will have to puncture the gypsum layer," said a senior government official.

In neighbouring Nepal, at least six people were killed and dozens of villagers were missing after monsoon flooding and landslides hit houses, schools and villages across the Himalayan nation.

Nepal's home ministry spokesman, Baman Prasad Neupane, said flood waters had seriously hit Achham district, 350 km (220 miles) west of the capital, Kathmandu.

"About 100 houses have been damaged in landslides in two villages in Achham district where flood waters also washed away a small hydroelectric plant," said Neupane.

"Army and police rescue teams have been rushed to the site and hundreds of people have been moved to safe locations," he said, adding that at least five people were missing.

In India's Barmer district, hundreds of desperate villagers scrambled for food packets dropped by helicopters. Many whose homes have been flooded or collapsed are living huddled in tents of plastic sheets.

People saved themselves by hanging on to the branches of trees as flood waters swirled beneath them, TV channels reported.

"I have never seen so much water," Thodi, an elderly woman with a heavily lined face, told CNN-IBN television. "It has destroyed everything."

A train service between India and Pakistan that runs from Munabao in Barmer to Kokhrapar in southern Pakistan has been suspended because of the floods.

Bodies of thousands of cattle were floating in the flood waters, causing a foul smell in some areas and raising concern about the spread of disease.

The Rajasthan government has dispatched several medical teams to the district.

In western and southern India, hundreds of people have been killed and millions left homeless since the annual monsoon rains started in June.