India has signed a deal with Russia to buy five top-range missile defense systems. Many consider it a landmark agreement that strengthens India-Russia relations even further. The deal came during a summit between Russian President Vladimir Putin and Indian Prime Minister Narendra Modi. The two countries also signed a number of other deals, and decided to cooperate further on international forums. Meanwhile, the US had warned India of sanctions if it finalized the defense deal with Russia.

It was a meeting between two of the world's most powerful leaders - Russian President Vladimir Putin and Indian Prime Minister Narendra Modi.

This against a backdrop of tense global geopolitics.

All eyes were on the defense deal between India and Russia, following US threats of sanctions on Delhi if it went ahead.

The bonhomie between Modi and Putin was visible, and led to what was widely expected. India ordering five Russian S-400 Triumph surface-to-air missile squadrons, and ignoring the US warning.

VLADIMIR PUTIN RUSSIAN PRESIDENT "Our cooperation goes beyond supplies of Russian weapons between our countries. We produce jointly, and develop modern military products. We maintain regular contacts between our ministries of defense and other details of our countries."

The defense deal between India and Russia is valued at 5.4 billion US dollars. India considers the S-400s critical for its defense capabilities. The system can track up to three hundred targets simultaneously, and protect large tranches of land including towns or important areas in a war. The plan is to combine the strength of the S-400 with the Indian Air Force's own defense network. The defense system is to be fully delivered by 2020. Russia and India have also agreed to work in space exploration together, including on India's first ever mission to send an astronaut into space in 2022.

NARENDRA MODI INDIAN PRIME MINISTER "Our new goal, in the sector of space, is to send Indian astronauts into space under the Indian Gaganyaan programme. I was told by Putin that we will get full support from Russia."

India may still be able to get the US to waive the threatened sanctions.

Notably, when China purchased S-400 anti-missile system from Russia, Washington objected and sanctioned Beijing.

But India is different. The US wants India to be an ally in Asia, and a partner in countering China's rising power in the region.

Trade was another key topic for discussion, as volumes between the two countries reached 10 billion dollars last year.

The leaders have vowed to triple this to 30 billion US dollars by 2025 further drawing the two powers closer together.

Shweta Bajaj, CGTN, New Delhi, India.