Twenty-four students are feared dead after being washed downstream by a sudden surge of river water in a remote Himalayan valley in northern India, officials have said.

The engineering students had stopped to take photographs on the edge of the Beas river in Himachal Pradesh on Sunday evening when water released from a dam washed them downstream, Transport Minister G S Bali said.

Rescuers in rafts and boats were seen searching the Himalayan river on Monday and police said four bodies had been found.

A local official blamed the surge of water on a hydroelectric power plant further upstream.

"The water was released by the Larji power project dam," said senior state official Rakesh Kanwar said.

Search operations have been launched to trace the missing students but there had been no success due to the darkness, a local news agency PTI reported.

Quoting state officials, it said the chances of finding the missing students alive are dim.

Angry protests

Angry locals and tourists blocked the main highway near the river in protest over the incident, saying authorities had failed to issue a warning about the release of water from the dam, according to local media.

The students, from the VNR Vignana Jyothi Institute of Engineering and Technology in the southern city of Hyderabad, had been travelling to the resort town of Manali further north.

The picturesque Kullu Valley is home to raging rivers, dense forests and steep gorges.

Himachal Pradesh and other Himalayan states including neighbouring Uttarakhand are home to a string of hydroelectric projects as India rushes to expand power generation to meet rising demand.

Governments are attempting to harness the power of rivers, despite the risk of environmental damage, to diversify away from costly and polluting coal and gas plants to meet the country's electricity shortage.

A government report in April concluded that hydropower projects in northern India were partly to blame for devastating floods last year that killed thousands.

Source: Agencies