New Delhi - Floods and landslides triggered by heavy monsoon rains have affected 900,000 people in three eastern Indian states as the death toll climbed over 30, officials and news reports said Wednesday.

Electricity supplies, road and train services were disrupted as floods submerged huge areas in the northern districts of Orissa state since Tuesday, the IANS news agency reported.

"The total number of people affected would be about half a million," B Baral, Orissa's senior relief official, told IANS news agency. He said the situation was likely to worsen with rains continuing to pound the region on Wednesday.

The NDTV network reported that five people died in rain-related accidents in Orissa, including one car carrying three people that was swept away by flood waters.

Local agencies in the four districts of Belasore, Mayurbhanj, Keonjhar and Bhadrak were put on alert as rivers crested during the monsoon.

Flooding in the north-eastern state of Assam since Saturday also reaped tragic tolls.

"The floods have left eight people dead and displaced nearly 400,000 people in 359 villages in Lakhimpur and Sonitpur districts," said Nandita Hazarika, an official in the state flood-control room.

Although the rains had eased since Tuesday night, Assam state authorities issued a health alert as teams of doctors and paramedics fanned out to the affected regions to prevent the outbreak of waterborne diseases.

"Scores are in makeshift shelters and an estimated 20,000 in relief camps as their homes are either marooned, or filled with mud or slush," she added.

On Saturday, a series of mudslides in the adjoining Arunachal Pradesh left 19 people dead and about 15 injured in and around the state capital Itanagar.

Heavy rains also pummelled India's eastern metropolis of Kolkata since Monday, submerging large areas of the city.

The monsoon season in India lasts from June to September.

The seasonal rains in 2007 were the most devastating in recent memory, with more than 3,200 people killed across several Indian states. More than 57 million people, most of them living in rural areas, were affected by the flooding. (dpa)