India had signed the missile deal in October 2018 during Russian President Putin's visit. The deal was worth $5 billion ensuring the advanced long-range surface-to-air missile would become a key weapon in India's arsenal.
However, the Trump administration had warned that the deal would have serious implications for India even though no specific details were put forward by the US.
India feared US sanctions under the Countering America's Adversaries Through Sanctions Act (CAATSA) instituted by the US Congress on arms purchases from Russia, but it did not transpire after Indian officials communicated India's defence requirements to Trump's officials.
The Indian government in the Parliament said that ''It takes Sovereign decisions based on threat perception, operational and technological aspects to keep the Armed Forces in a state of readiness to meet the entire spectrum of security challenges."
India's external affairs minister S Jaishankar will be visiting Moscow by the end of August during which he will be meeting Russian foreign minister Sergey Lavrov.
India will be getting all the units of Russian S-400 by April 2023. The announcement was made by the minister of the state of defence Sripad Naik in a written statement in Lok Sabha.