"Russia has been India's foremost defence partner through decades, accounting for a majority of our defence equipment... Even in the current environment, despite India's improved access to the world market, Russia remains our principal partner," Modi told Russian news agency Itar-Taas.
Noting that Russia provided defence equipment to India and international support when few were willing to hold its hands, the Prime Minister said, "Indians will never forget the Russian support that we got when we needed it the most."
India and Russia are likely to ink a number of pacts in a range of sectors including defence and nuclear energy during Modi's two-day visit here beginning today for the annual Summit level talks with President Vladimir Putin.
Asserting that the Indo-Russia defence ties have been transformed "from a buyer seller relationship to one involving joint research, development and production of advanced systems" such as the Brahmos missile, Sukhoi-30 MKI aircraft and T-90 tanks, Modi said Russia has the potential to be the leading partner in Make in India mission in defence sector.
"We are soon going to make a beginning in that direction," Modi said.
"We are also working together for joint manufacture of defence equipment and components in India under the Make in India initiative," he added.
India's assurance to Russia comes at a time when it has developed a closer defence ties with the US and Russia made overtures to Pakistan in recent months for the first time.
On the civil nuclear cooperation, Modi said India is committed to construct at least 12 nuclear power plants having highest safety standards in the world with Russian assistance.
"Energy security is critical to India's economic development and Russia is a key partner in this area. Nuclear energy is an important component of our energy security strategy. Russia is currently our leading international partner. Our cooperation with Russia in the peaceful uses of nuclear energy is a cornerstone of our strategic partnership," he said replying to a question.
"I am glad that the Kudankulam Nuclear Power Project has become operational, and is set to expand. I believe our cooperation in the area of nuclear energy will continue to grow. After Kudankulam, we are finalising a second site for Russian-designed reactors in India," he said.
"We have outlined an ambitious vision for nuclear energy and construction of at least 12 reactors, which will have the highest safety standards in the world," Modi added.
The Prime Minister said the strengths of Russia in science and technology, military technology and nuclear energy among others complement the large market of India, expanding economy and demand of its young population.
"This provides us with the confidence that we can take forward our existing dynamic partnership," he added.
On cooperation between the two sides on international and regional forums, Modi said a strong international partnership has been the hallmark of the bilateral ties and the Russian support in international forums, including in the UN Security Council, through the decades is deeply valued in India.
"Today, our international cooperation has widened. We work together in a number of international forums, including BRICS, Shanghai Cooperation Organisation (where Russian support helped in a decision on India's full membership this year), G 20 and East Asia Summit.
"BRICS, which was launched by President Putin, is making a major contribution to international finance and trade, development finance, international terrorism, climate change, food security and sustainable development," he said.
"In both SCO and East Asia Summit, we can work together in advancing peace and prosperity in two major regions of the world, where we both have vital stakes. Multipolarity is a global reality. India and Russia represent two faces of a multi-polar world. We want to work with Russia not just for our bilateral interests, but also for a peaceful, stable and sustainable world," the Prime Minister added.
On economic ties, Modi said there is potential to further strengthen the Indo-Russia relations in the field of trade and investments.
"Our bilateral trade, though growing, has not achieved its full potential. We have committed to increase this to $30 billion by 2025. Similarly we are committed to increase our investments to $15 billion each by 2025," he said.