Ahead of his two-day official visit to Moscow during which the two sides are set to ink important bilateral agreements, Indian Prime Minister Narendra Modi has lauded the country’s historical ties with Russia.

“Russia remains one of India’s most valued friends in the world,” Modi said in New Delhi on Wednesday before leaving for Moscow. He will hold “extensive deliberations with President Putin”, according to a statement posted on the website of the Prime Minister’s Office.

“Today I will commence my visit to Russia, my first bilateral visit after we formed the Government. I am very optimistic about the outcome of this visit. History is witness to the close ties India and Russia have had over the decades,” he added.

The Indian government last week approved the procurement of five Russian S-400 air defence systems, Russia’s most advanced air and missile defence system with extraordinary reach.

With a range of 400 kilometres, S-400 Triumf is designed to shield from air strikes, strategic, cruise, tactical and operating tactical ballistic missiles and medium-range ballistic missiles.

The deal is likely to be discussed during the December 23-24 Russia visit of Modi when he holds talks with Russian President Vladimir Putin. China became the first foreign customer of the S-400  earlier this year.

The upcoming Indo-Russian deal, estimated to be worth around 400 billion rupees ($6 billion), also covers the purchase of about 6,000 missiles, a mobile launcher and a radar station, according to Indian media reports.

On Wednesday, the Indian leader said New Delhi will boost ” economic, energy and security” cooperation with Moscow. India has also said it is launching negotiations on a Free Trade Agreement with the Russia-led Eurasian Economic Union bloc.

“We also want to increase cooperation in science and technology, mining among other sectors. Trade ties between India and Russia can increase even further, to benefit not only our two nations but also the world,” Modi said.

Modi will also meet Russian business heads urging them to invest in India.

The two sides have set a bilateral trade target of $30 billion by 2025 and bilateral investments to $15 billion each by 2025. Currently, bilateral investment stands at around $11 billion.

In an interview to Russian agency Tass, Modi said “BRICS can be an important voice in advancing a more equitable and inclusive global order”.

“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.

Russia is an unwavering ally of India in global affairs, Modi noted.

“In the global environment, in times of crisis, where you need a friend, Russia has always stood with us. We never had to wait to know what Russia will do with us in this regard. We remain confident that we are doing this, Russia will do the same with us,” he said.

Modi also praised Putin saying he has provided “excellent leadership to Russia” and one who is “willing to sacrifice to maintain relations”.

“There are those who think something, but say something else. This I have not experienced with President Putin,” said Modi.

“Whenever there is a crisis in the world, Russia comes up with its own ideas with its strength,” he added.

“Russia provided defense equipment to India and international support when few were willing to hold our hands. Indians will never forget the Russian support that we got when we needed it the most,” Modi told Tass.

Russia and India need to invest more in energy ties, Modi has urged.

“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. I am glad that the Kudankulam Nuclear Power Project has become operational, and is set to expand,” Modi said.

Moscow has already reached an agreement with New Delhi to construct 12 nuclear power plants in India.

In Moscow, Modi will hold talks with Putin and Russian Premier Dmitry Medvedev, following which the two sides will sign an array of cooperation agreements in energy, finance, space and defence.

India will push for joint manufacture of defense equipment and components in India under Modi’s pet initiative, the ambitious “Make in India” campaign.

Russia’s aerial campaign against terrorism in Syria, and the broader fight against the Islamic State group will also be discussed in talks between Indian and Russian leaders.

“None of the terrorist groups have their own factories for manufacturing weapons. It means that there are some countries which have weapons and provide them. Which is that route? Why is it not being blocked? The terrorists do not run any money printing machine. Where from the money flows the world over? Where from the strength comes for such big battles? Whether it is funding or communication technology, the governments of the countries of the world can play one or other role,” Modi said.