At least 100 people have been killed in landslides and floodwaters in Nepal following four days of torrential monsoon rains, an official said on Monday. Another 120 people are believed to be missing.

The downpours have damaged roads and homes, isolating dozens of villages in the Himalayan nation's southern plains region. As rain eased on Sunday, 3,400 rescue workers and three helicopters were deployed to evacuate residents and get supplies to people in the worst-hit areas.

"The flood has destroyed our water pipes, our roads and cut off our electricity, making it difficult for us to carry out necessary search and rescue operations," district official Jagat Bahadur Basnet told AFP.

The latest rain comes two weeks after a landslide in the country's northeast killed 156 people.

Cholera fears

Authorities in the severely affected districts of Surkhet, Bardiya and Dang, have warned of a possible outbreak of cholera, and are scrambling to provide villages with clean drinking water kits and food.

"We have diagnosed a few cases displaying symptoms of cholera … people suffering from fever, dysentery, diarrhea are being treated at nearby health posts," Tulashi Prasad Dahal, who is coordinating the health ministry's efforts to prevent an epidemic, told AFP.

Cholera is transmitted by consuming water or food that has been contaminated by human feces. It causes vomiting and diarrhea and can be fatal.

Flooding across the border

Meanwhile, dozens of people have died in floodwaters in neighboring India since Friday, local officials said.

At least 25 people were reported killed in landslides, house collapses and flash flooding in the Uttar Pradesh state, where the swollen Rapti and Ghagra rivers are in spate after Nepal released water from its barrages to ease the situation there.

A further 34 Indians have died in Uttarakhand state, where a deadly deluge killed some 5,000 people last year.

Authorities in India's Himalayan region are working to get emergency supplies, including medical kits, tents, plastic sheets, cooking utensils and clothing, to thousands of villages that have been cut off by floodwaters.

India's monsoon season lasts from June to September, and often results in loss of life, as well as wreaking havoc on local farmland and homes. More rain is forecast in the flood-affected regions over the next few days.

nm/sb (AFP, AP, dpa)