Nearly 150 people are believed to have died in flash floods in the northern Indian State of Himachal Pradesh, authorities in the area said.

The state's chief minister, Prem Kumar Dhumal, who surveyed the area from a helicopter said the floods had taken a heavy toll of life and property.

The floods came late on Monday in the Himalayan region. The Sutlej river, which normally runs in a deep gorge, overflowed in matter of minutes.

The BBC correspondent in Delhi, Satish Jacob, says a torrent of water swept away a bridge as a bus was crossing it.

Widespread damage

The majority of deaths are believed to have occurred in the Kinnaur district.

Many areas in the district of Kulu, Mandi and Simla have been cut off from the rest of the country, with communication impossible.

According to the chief minister, at least 15 bridges have been cut off.

A hydroelectric power plant which is under construction in the area has also been damaged.

Mr Dhumal said the floods were caused by a cloudburst in southern Tibet.

He has asked the Indian central government for financial help to overcome the effects of the disaster.

Many landslides have been an common occurrence in the region over the last few years.

Environmentalists say massive deforestation in the hills is the main reason for these incidents.