The first squadron of India's recent acquisition of Russian S-400 "Triumf" surface-to-air systems was deployed in the Punjab "sector" along the Pakistani border on Monday, the Indian news agency ANI has reported.
"The batteries of the first squadron would be capable of taking care of aerial threats from both Pakistan and China", the report quoted officials as saying.
The S-400s are equipped with four different types of missiles -- short-range 9M96E (40 km), medium-range 9M96E2 (120 km), long-range 48N6 (250 km), and very long-range 40N6E (400 km).
Indian officials have further said that parts of the advanced air defence system are still being delivered to India from Russia through air and sea routes. The ongoing deployment will be completed soon and the unit will be operational in a few weeks, Indian officials say.
As per the report, the deployment of the next S-400 squadron will take place on the eastern border with China.
The eastern Ladakh region along the India-China border is the site of an unresolved military standoff between the two Asian giants.
According to reports, two S-400 units are currently deployed by China at the Ngari Gar Gunsa and Nyingchi in the Tibet Autonomous Region (TAR).
India signed a $5.43 billion deal with Russia in 2018 for the delivery of five columns of S-400 systems by 2023. At the time, Pakistan said that the S-400 deal would "further destabilise strategic stability in South Asia" and incite a "new arms race".
The Russian systems are being placed under the command of the Indian Air Force (IAF).
As per New Delhi, the deliveries of parts of the first squadron from Russia began this month, ahead of Russian President Vladimir Putin's visit to New Delhi on 6 December.
"… supplies have begun this month, and will continue to happen", Indian Foreign Secretary Harsh Vardhan Shringla said during a press briefing after the 6 December meeting between President Putin and Indian Prime Minister Narendra Modi.
The Indian PM and the Russian president also held their first telephone conversation since the 6 December meeting on Monday.
"The leaders discussed the practical aspects of efforts to implement the agreements reached following the talks. They expressed a mutual intention to continue the further all-round development of relations of the special privileged strategic partnership between Russia and India", a release by the Kremlin said.
According to the official release, Putin and Modi also spoke about "international stability and security problems, including the situation in the Asia-Pacific" during their call.