Indian Prime Minister Narendra Modi has signed a deal with Russian President Vladimir Putin on Saturday (15 October) to acquire an advanced air defence system from Moscow that is worth over $5bn (£4.1bn).

The deal is reported to be one among the 16 key agreements that both the countries have signed on the sidelines of the Brics summit. India is hosting the Brics meeting in Goa on 15 and 16 October, with leaders from Brazil, Russia, China and South Africa participating.

The pact includes S-400 Triumph, a long-range air defence missile system that has the capability to destroy any incoming hostile aircraft or drone at ranges of up to 400km, according to local media reports. Delhi has now purchased five of these systems. The same defence system is said to be deployed in Syria too.

Modi welcomed Putin to India with a Russian saying: "An old friend is better than two new friends."

He also signed a joint venture to build 200 multi-task Kamov 226T helicopters in India. The twin-engine helicopters are reportedly meant to replace India's ageing Cheetah and Chetak aircraft.

In addition, an agreement to build frigates for the Indian Navy has also been signed by Modi and Putin. These defence pacts are reported to be a part of Modi's drive to upgrade India's Soviet-era military hardware and to build a defence industrial base in India.

Apart from signing the defence deals, India and Russia also spoke at length about combating terrorism. Both the leaders are reported to have shared similar views on cross-border terrorism.

"We deeply appreciate Russia's understanding and support of our actions to fight cross-border terrorism that threatens our entire region," Modi said.

"President Putin and I noted the similarity of our views on the situation in Afghanistan and turmoil in West Asia. We both affirm the need for zero tolerance in dealing with terrorists and their supporters," Modi added.

The Indian prime minister is expected to meet Chinese President Xi Jinping later in the day.