-With agency inputs

NEW DELHI: India on Friday inked $5.43 billion (Rs 40,000 crore) deal to purchase five advanced S-400 Triumf surface-to-air missile squadrons from Russia, despite the looming threat of US financial sanctions.India and Russia signed the missile deal after annual summit talks between Prime Minister Narendra Modi and Russian President Vladimir Putin in Delhi.The United States has warned that countries trading with Russia's defence and intelligence sectors would face automatic sanctions under a sweeping legislation called Countering America's Adversaries Through Sanctions Act (CAATSA) that President Donald Trump signed into law last August.The law is designed to punish Putin for the 2014 annexation of Crimea from Ukraine, involvement in the Syrian civil war and meddling in the 2016 US presidential election.The S-400 is an upgraded version of the S-300 systems. The missile system, manufactured by Almaz-Antey, has been in service in Russia since 2007.Once India inducts the highly-mobile and automated S-400 systems, which have different kinds of supersonic and hypersonic missiles as well as long-range radars to track 100 to 300 targets simultaneously, they can be used to protect cities during war or vital installations like nuclear power plants.The plan is to fully integrate the S-400 systems with the IAF's air defence network called IACCS (integrated air command and control system), which combines a wide array of sensors and weapons, to further enhance their lethality and plug gaps in the country's airspace.China, incidentally, has already begun to induct six S-400 batteries, which is designated the 'SA-21 Growler' by NATO, under a $3 billion deal inked in 2014.