CHENNAI: A south Indian fisherman was killed on Monday after police opened fire to clear a highway blocked by demonstrators protesting against the country's largest nuclear power project, due to start up within weeks after months of opposition.

Hundreds of protesters threw stones at police lines and also blocked a rail route, a police official told Reuters. Police responded by firing a volley of bullets in the air, killing one protester, the police official said. Other demonstrators set fire to a local government office.

Earlier, police used tear gas to break up thousands of protesters on a beach near the Kudankulam nuclear power plant, which is in the state of Tamil Nadu.

About 4,000 activists, mainly women and children from fishing villages, had camped on the beach about a mile from the plant to protest about the threat of radiation.

Protesters had waded into the sea or escaped in fishing boats as hundreds of police advanced on the beach. They threw rocks at police and several injuries were reported by both police and the protesters.

The Kudankulam plant is due to open within weeks and will provide 2 gigawatts of electricity, enough to power millions of Indian homes and relieve a power crisis in the state of Tamil Nadu. More nuclear plants are planned.

The government's Atomic Energy Regulatory Board last month gave clearance for fuel to be loaded into one of the Kudankulam plant's two reactors, one of the last steps before it can begin producing power.

India is struggling to meet surging demand for electricity and suffers from a peak-hour power deficit of about 12 percent, which has become a significant drag on the economy. A grid failure on two consecutive days this summer caused one of the world's worst blackouts.

First conceived in 1988, Russian-built Kudankulam was supposed to have gone into operation last year, but protesters surrounded the compound after an earthquake and tsunami hit Japan's Fukushima Daiichi nuclear plant, causing radiation leaks and forcing mass evacuations.

The protesters fear a similar accident could happen in southern India, a region that was hard hit by the 2004 Indian Ocean tsunami.

India's home minister accused foreign NGOs (non-governmental organisations) for supporting the anti-nuclear protests in the state.

“We are aware that some foreign NGOs are very interested in this. I do not want to name those countries, but we are aware of it,” Home Minister Sushilkumar Shinde told reporters in New Delhi.

Prime Minister Manmohan Singh also blamed NGOs for funding protests in an interview published in Science magazine earlier this year.

India plans to add 63 gigawatts of nuclear power by building 30 reactors by 2032. Nuclear accounts for less than 3 percent of total capacity.

But the country aims to increase power capacity over the next five years mainly through coal, which already accounts for 60 per cent of India's energy generation. Environmental concerns and mismanagement have slowed growth there as well.

There have also been protests in coal fields in the centre of the country, while hydro power projects in the Himalayas have faced opposition from local tribes.