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NEW DELHI: India has now begun final contract negotiations with Russia for the Rs 39,000 crore (over $5.5 billion) acquisition of five advanced S-400 Triumf air defence missile systems , which can detect, track and destroy hostile strategic bombers, stealth fighters, spy planes, missiles and drones at a range of up to 400 km and altitude of 30 km.India wants to conclude the major deal in the 2018-19 financial year, with the first S-400 surface-to-air (SAM) missile system, with its associated battle-management system of command post and launchers, acquisition and engagement radars, and all-terrain transporter-erector-launcher vehicles, slated for delivery two years after the contract is inked."All the five S-400 systems, which can even take on medium-range ballistic missiles, apart from cruise missiles, will be delivered in 54 months. The force-multiplier will change the dynamics of air defence in the region," a defence ministry source said.India's final commercial negotiations with Russia after extensive field trials come at a time when China has already begun to get deliveries of six S-400 batteries - designated 'SA-21 Growler' by NATO - under a $3 billion deal inked in 2014.There were, however, reports that some auxiliary components of the S-400 systems being shipped to China from Russia were damaged in a storm last week. Russia, which has deployed the S-400 in Crimea for airspace protection along the Ukraine border, is also set to sell the air defence systems to Turkey and Saudi Arabia.India can deploy the highly-mobile S-400 system to protect a city during war, or even use it to neutralise Pakistan's short-range Nasr (Hatf-IX) nuclear missiles. Pakistan often recklessly brandishes its Nasr missiles as a battlefield counter to India's 'Cold Start' strategy of swift, high-intensity conventional attacks into enemy territory.With long-range radars to track 100 to 300 targets simultaneously, the S-400 has different kinds of supersonic and hypersonic missiles to intercept incoming aerial threats at different ranges. The system's cost depends on the configuration a customer wants. India, for instance, is mainly going in for long-range (120-370-km) interception missiles.TOI was the first to report in October 2015 that the Defence Acquisitions Council (DAC) was finalising the game-changing acquisition of the S-400 systems to plug major operational gaps in airspace defence.After clearance from the DAC in December that year, the Modi-Putin summit in Goa in October 2016 led to inking of inter-governmental agreements for five S-400 systems, four Grigorivich-class frigates and 200 Kamov-226T light helicopters, while the two also sealed the lease of a second nuclear-powered submarine after INS Chakra, all together worth around $10.5 billion, as was then reported by TOI.When the S-400 contract is actually inked, it will be among the largest-ever deals with Russia. The other big deals include the ones for 272 Sukhoi-30MKI fighters (over $12 billion) and INS Vikramaditya ($2.33 billion for the aircraft carrier and another $2 billion for 45 MiG-29Ks to operate from its deck).