New Delhi, Dec 5 : India and Russia signed a landmark agreement on civil nuclear cooperation today.

Prime Minister Dr. Manmohan Singh said while addressing a joint press conference with Russian President Dmitry Medvedev in New Delhi today that Moscow would build four additional atomic reactors in the Koodankulam nuclear plant in Tamil Nadu.

The deal will allow Russia to build more reactors at the Kudankulam nuclear power plant and plants in other parts of the country.