India and Russia say plans have been finalised for Moscow to build four new nuclear power stations in India.
The two countries say that relations are getting warmer
Delhi needs civilian nuclear technology from abroad to meet its target of producing more nuclear power by 2020.
The two countries also decided to step up cooperation in defence, engineering and energy. They hope that bilateral trade will double to $10bn by 2010.
Delhi and Moscow have had close links since Soviet times. In November they agreed to boost military ties.
"We have finalised negotiations... on building additional nuclear power plants in India," Prime Minister Manmohan Singh said after meeting his Russian counterpart, Victor Zubkov.
Correspondents say that under the terms of the deal, Russia will build four additional reactors at Kudankulam in the southern Indian state of Tamil Nadu.
Moscow is already building two 1,000 megawatt light water nuclear power reactors at Kudankulam under the terms of an agreement made in June 1998.
India says it needs more nuclear energy
The two sides signed agreements on four power plants during President Putin's visit to India in January last year.
The agreements call for the "construction of four energy blocks at the atomic plant at Kudankulam''.
But officials say that the construction of new reactors will begin only after the Nuclear Suppliers Group, which controls global nuclear commerce, lifts a three-decade old embargo on atomic trade with India.
India is also negotiating with the International Atomic Energy Agency to lose its status as a nuclear pariah following nuclear tests in 1998.
Mr Singh said India and Russia realised that their defence ties were an "important pillar" of their strategic partnership.
The two countries are also rapidly deepening co-operation in the energy sector.
Russia accounts for about 70% of Indian military equipment, but correspondents say that late deliveries and commercial disagreements have forced Delhi to use other suppliers including Britain, France, Israel and the US.
Mr Zubkov said that trade between the two countries between 2006 and 2007 grew by 30%, touching $5bn.
"If the speed remains the same, I am confident the 10 billion dollar mark will be achieved," he said.