11 December 2014 Last updated at 13:48 GMT
Russia will help India build at least 10 more nuclear reactors, Indian Prime Minister Narendra Modi has said following a visit by Russian President Vladimir Putin.
The two countries signed a series of major energy agreements on Thursday.
Russia will also remain India's top defence supplier, said Mr Modi.
Mr Putin's visit to Delhi comes as India faces energy shortages and Russia seeks to expand its ties with Asia in the face of Western sanctions.
Mr Modi said that the two countries had outlined an "ambitious vision"for nuclear energy during the talks and that the new reactors would be built over the next 20 years.
He added that, under the deal, nuclear components would be made in India.
A $1bn (£630m; €800m) joint venture to support hydro-electric power projects in India has also been agreed, according to Reuters news agency.
Meanwhile Russian oil producer Rosneft signed a deal to supply India with 10 million tonnes of oil per year, Reuters said.
Mr Putin said earlier that his country was looking to export more Russian oil and gas to Asia because of problems with the European market.
A project to build a new gas pipeline to Europe, known as South Stream, was cancelled last week amid concerns that it could be in breach of EU competition rules.
Also, the crisis in Ukraine has led to a bitter fall-out between the West and Russia, which has been placed under wide-ranging sanctions by the US, EU and several other countries.