Indian Prime Minister Narendra Modi on Monday said that ties between India and Russia will continue to scale newer heights following an informal summit he held with Russian President Vladimir Putin here.

"Extremely productive discussions with President Putin," Modi tweeted.

"We reviewed the complete range of India-Russia relations as well as other global subjects," he said.

"Friendship between India and Russia has stood the test of time. Our ties will continue to scale newer heights in the coming years."

Earlier, Modi said that his informal summit with Putin will take bilateral ties to a new level.

"I am happy that today I got the opportunity to be a guest of President Putin and that too in Sochi," Modi said after being received with a warm hug by Putin at his summer residence, Bocharev Creek, in this resort city on the Black Sea coast.

"Russia has always remained a true and fast friend of India," he said.

"We have been regularly holding bilateral meetings but I am grateful to President Putin for inviting me for an informal summit which has taken our relationship to a new level."

On his part, Putin said that there is no need to explain Russian-Indian relations, since these have deep roots.

"However, we have been able to create additional momentum recently. Last year, our trade saw a significant increase, adding another 17 percent since the beginning of this year," he said.

Stating that Russia and India are proactive in their foreign policy cooperation, including within international organisations such as the UN, BRICS (Brazil, Russia, India, China, South Africa) and now the Shanghai Cooperation Organisation (SCO), Putin said: "We have established close contacts and collaboration between our defence agencies. All this is indicative of the high level of strategic relations between our countries."

Modi arrived here earlier on Monday on a nine-hour visit for the informal summit proposed by Putin soon after his reelection as Russian President.

The Indian leader's 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.

The sanctions against Russian oligarchs and companies, including Rosoboronexport, the state-owned Russian weapons trading company, has raised concerns in India about a possible impact on India's military buys from Moscow.

The withdrawal of the US from the Iran nuclear deal can be seen as another major reason for the informal summit.

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

The relationship between India and Russia was elevated to that of a Special and Privileged Strategic Partnership during Putin's visit to India in 2010.

In his remarks, Modi congratulated Putin for being reelected for the fourth time with a huge majority.

"Since 2000 when you assumed this office, you have maintained a close relationship with India," he said.

"When you came to India for the first time after becoming President and when Atal Bihari Vajpayee was the Prime Minister of India, you said very eloquently back then that India and Russia were ancient civilisations and vibrant democracies. People of India still remember this."

Stating that Russia and Putin specifically hold special significance in his own political journey, Modi said in 2001, after he became Chief Minister of Gujarat, within one month he got the opportunity to visit Russia along with Vajpayee.

"In Moscow, as Chief Minister, the first world leader I met was you and in a way I got introduced to foreign relations through you," he said.

Recalling that 18 years ago, Vajpayee and Putin sowed the seeds of the India-Russia Strategic Partnership, Modi said: "Together, both of us can today proudly say that the seeds that Atalji and you sowed have grown to a Special and Privileged Strategic Partnership. This in itself is a very big achievement."

The Indian leader said that he too had the chance to work shoulder-to-shoulder with Putin for the last four years whether it be bilateral relations or international ties and he was "happy about it".

Repeating Vajpayee's words in 2000 during Putin's visit, Modi said that being a friend of Russia for a long time, India would like to see Russia as a powerful and confident nation, which, in a multipolar world, can play a significant role.

"It is a matter of happiness for us that whether it be the SCO, in which you have played a very big role for India's membership, the BRICS, CECA (Comprehensive Economic Cooperation Agreement) or the (International) North-South Corridor, we have been working together in a number of mechanisms and have successfully moved forward," the Indian Prime Minister said.

He also extended his best wishes to Russia for hosting this year's FIFA World Cup.

Following Monday's summit, Modi and Putin took a boat ride on the Black Sea and, according to Indian External Affairs Ministry spokesperson Raveesh Kumar, the two leaders "had plenty to discuss".

The Sochi meeting came after a similar informal summit Modi held with Chinese President Xi Jinping in China last month.