Russian President Vladimir Putin has arrived in New Delhi on a two-day visit which is likely to focus on the signing of a 5 billion dollar deal for India to procure Moscow's most advanced air defence systems, the S-400 Triumf, despite the risk of US sanctions against countries buying Russian defence equipment. India wants to procure the long-range missile systems to tighten its air defence mechanism, particularly along the nearly 4,000-km-long India-China border. Vladimir Putin and Prime Minister Narendra Modi will also discuss key regional and global issues, including US sanctions on import of Iranian crude oil.