“Russia and India are very old friends,” said Prime Minister Narendra Modi as he hailed the close relationship between the two countries in his meeting with Russian President Vladimir Putin on Monday.

The PM, who is visiting the Black Sea city of Sochi for an informal summit with the Russian leader, extended his thanks to Putin for the invitation.

“I am grateful to President Putin for inviting me for an informal meeting. This adds a new dimension to our relationship,” he said while congratulating Putin for winning a fourth term in office.

Recalling the 65-year-old Russian strongman’s first visit to India during the premiership of Atal Bihari Vajpayee, Modi said that people of India still cherish Putin’s remarks on the common ties, the ancient culture and vibrancy of the democracies that bind the two nations.

“Russia played a major role in helping India get a permanent membership in SCO. We are working together on International North-South Transport Corridor (INSTC) and BRICS,” said Modi underlining Russia’s endorsement for India on the international stage.

Modi acknowledged the efforts of both Vajpayee and Putin in transforming India-Russia relations into a strategic partnership.

“The seed of the strategic partnership has now grown into a tree called special strategic partnership,” said Modi.

Commenting on the annual bilateral summit between the two countries, Modi said that it has been going on uninterrupted for the last 18 years. India holds annual bilateral summits with only two countries – Russia and Japan.

“You have added a new dimension, ‘informal summit’, to our relation which in itself increases the trust between the two nations,” said the PM, who is on his fourth visit to Russia since coming to power in 2014.

Welcoming Modi at Bocharev Creek in the city, Putin drew attention to the defence ties between the two countries.

“Our militaries maintain very close contacts and cooperation. It speaks about a very high strategic level of our partnership,” he said.

The Russian leader also hailed joint activities of the two countries in the area of foreign politics, in particular within the UN, BRICS (an association of Brazil, Russia, India, China and South Africa), and the Shanghai Cooperation Organisation (SCO).

Modi arrived in Sochi on Monday afternoon for a nine-hour tour. His visit comes after National Security Adviser Ajit Doval and Foreign Secretary Vijay Gokhale visited Moscow earlier this month to discuss a way out of the US sanctions on Russian firms.

US sanctions against Russia under the Countering America’s Adversaries through Sanctions Act (CAATSA) might impact the Indo-Russia defence cooperation, which is what the two leaders are likely to study.

Sanctions may have a possible impact on India’s military purchases from Moscow. The two leaders are also expected to discuss the Indo-Russia civil nuclear cooperation to third countries.

“Both leaders will discuss their respective national developmental priorities and bilateral matters,” read a statement from the External Affairs Ministry.

Modi has previously visited Russia for the 2015 BRICS summit, a state visit in December that same year, and the 2017 annual summit.

Putin is expected to visit India later this year for the annual bilateral summit.

Modi’s meeting with Putin comes after his meeting with Chinese President Xi Jinping in a specially observed development in late April this year.