Some people were sheltering on elevated railway tracks and highways while others were forced to stay up trees and lamp posts without food and water.

Millions of people have been affected by the floods in West Bengal and neighbouring Bangladesh, said to be the worst monsoon rains for 20 years.

Risk of disease

International Red Cross official Fernando Soares said some areas had been flooded for as long as two weeks.

One man had to swim 10 km to get supplies for his family, he said, adding that the water level in the man's village was up to his neck.

IRC medical officer Jari Vainio said that there was a risk of water borne diseases because of lack of access to clean drinking water.

According to doctors, hundreds of people were already suffering from gastro-enteritis in the worst-affected areas.

Bangladesh

Across the border in Bangladesh, conditions are said to be improving slowly although thousands are still waiting for materials to help them rebuild their homes.

Around 700,000 are still being sheltered in camps.

Hundreds of thousands are still homeless

The UN Resident Co-ordinator in Dhaka, Jorgen Lissner, said that more relief teams would be sent to affected areas.

UN food aid would be restricted to the most vulnerable groups as the government had enough food stocks to meet relief requirements.

Officials at the country's Flood Warning Centre said that waters were receding gradually in some districts but a local journalist told the BBC that there had been fresh floods in the coastal Satkhira district.

Thirty villages in the district have already been swamped following the collapse of a river dyke there two days ago which left people stranded on their rooftops.