Russia and India have signed weapons deals worth billions of US dollars, as President Vladimir Putin sought to boost ties during a visit to New Delhi.
A US$1.6 billion deal will see 42 fighter jets license-built in India from Russian components, and a US$1.3 billion contract was also signed for the purchase of 71 military helicopters.
The two countries have shared close ties since the Cold War, when Russia was the principal arms supplier to New Delhi.
Prime Minister Manmohan Singh said Moscow was one of India's strategic allies.
"Russia is a key partner in our efforts to modernise our armed forces and enhance our defence preparedness. A number of giant design, development and production products are underway in high-technology areas."
Speaking through an interpreter Mr Putin said the two countries are expected to sign a number of other major arms contracts and military agreements.
"We agreed to promote new projects including in the area of establishing joint ventures and the transfer of technologies. An important step in this direction is the signing of the contracts to supply helicopter equipment and supplying spare parts for the licensed assembly factories of aircraft Su-30 MKI."
Russia has long been India's principal arms supplier, but has lost several multi-billion-dollar contracts to Western companies.
The two leaders also held talks on regional security.
Mr Singh said the two countries shared the goal of a peaceful Afghanistan.
"India and Russia share the objective of a stable, united, democratic and prosperous Afghanistan free from extremism, terrorism and external interference."
As part of its cooperation with India, Russia has built the first reactor at the Kudankulam nuclear power plant and is building a second unit.
The project has been delayed by protests by anti-nuclear groups and local residents.