Russia has offered to supply India with five additional squadrons of its S-400 Sudarshan long-range air defence systems. The proposal was submitted in response to a tender floated by the Defence Ministry — fast-tracking procurement plans soon after Operation Sindoor. The mobile, long-range surface-to-air missile developed by Moscow had played a key role in the short-lived clash with Pakistan and took out a large number of surveillance and fighter aircraft.
“The Russian response to the Indian tender has been received, and it is being processed at the moment. The project is estimated to cost over Rs 50,000 crore,” defence sources told news agency ANI on Sunday.
New Delhi has already received four S-400 squadrons under a 2018 contract with Russia — with a fifth expected to be delivered by November this year. The $5.43 billion deal is one of the many projects and agreements underway between the two countries. Several licensed production agreements have been implemented with Russian companies in India for Sukhoi-30 aircraft, T-90 tanks, BMP-2 armoured personnel carriers and more.
What is the S-400 Sudarshan unit?
The S-400 Sudarshan (named after the Sudarshan Chakra) is the Indian military redesign of a Russian advanced long-range mobile surface-to-air missile defence system. The S-400 Triumf air defence system uses a specialised panoramic acquisition radar to spot targets up to 600 kilometres away. It can also strike them at distances of up to 400 kilometres and help India counter enemy long-range air vectors targeting vital areas.
“The S-400 Missile is a potent system in terms of its operational capability to provide a continuous and effective air defence system to a very large area. With the induction of this system, air defence capability of the nation will be significantly enhanced,” Union Minister Ajay Bhatt told Parliament in December 2021.
According to the Russian state-owned Rostec, the system is “capable of engaging all types of aerodynamic targets as well as ballistic missiles”. The defence conglomerate also claimed that the Triumph system is “several times superior to its foreign counterparts in key performance characteristics”. It also noted, after a S-400 delivery to Turkey in 2019, that the system could be “integrated into global national air defence systems that comprise components manufactured by other countries without loss of functionality”.
Major role in Operation Sindoor
The S-400 had played a key rule during Operation Sindoor — taking out a large number of Pakistani surveillance and fighter aircraft while deterring others from even flying within 200 km of the Indian border. Defence Minister Rajnath Singh told Parliament soon after the attack that the neighbouring country had “used missiles, drones, rockets and other long-range weapons on India, in addition to technologies related to electronic warfare, on a large scale”. It targeted multiple Indian Air Force bases, army ammunition depots, airports and military cantonments. But the Indian air defence and counter-drone systems had completely foiled the attack, with various missile systems such as S-400, Akash and air defence guns working in tandem.
Former Western Air Command chief Air Marshal Jeetendra Mishra told ANI during a recent podcast that the S-400 had achieved what was possibly the longest-ever recorded surface-to-air missile kill when it destroyed a Pakistan Air Force surveillance aircraft at a range of 314 kilometres. He also confirmed that the missile system was responsible for taking out many Pakistani fighter aircraft, including the J-10s supplied to Islamabad by China.
“The Indian Air Force created a sort of world record. My S400 person asked shoot….I said shoot and when he shot we got him at 314 km. They had deployed spies within our country, activated their sleeper cell to find out where the S400 is…” the retired Air Marshal told ANI.
Singh added that the Indian security system had been “foolproof” during the strikes — with Pakistan “unable to hit” any of the targets or damage important assets. Mishra added that the S-400 had been fired from a distance of 314 kilometres, likely a record-setting distance for the weapon, to reportedly neutralise a large Pakistani aircraft. Use of the Russian systems had also effectively forced Pakistan to operate from greater standoff distances and prevented it from deploying long-range glide bombs against Indian targets.
Why is India doubling its S-400 fleet now?
According to an ANI report, the additional units are expected to be deployed along both the eastern and western fronts to strengthen India’s layered air defence network. Deliveries are currently being processed under the new contract and are likely to start about three years after the deal is signed. India had cleared plans to procure five additional squadrons of the Russian S-400 air defence missile system in March this year, soon after Operation Sindoor concluded.
The clash with Pakistan in May 2025 highlighted how India could counter (and even neutralise) an enemy force with just three S-400 systems in its arsenal. The tally will increase to five by the end of 2026 — with plans in motion to acquire five additional advanced long-range mobile surface-to-air missile defence systems. It is likely to become part of a stronger, multi-layered aerial shield upon installation.
US opposition and upcoming Putin visit
Reports suggest procurement may have been a topic of discussion as Russian President Vladimir Putin visited India in December 2025. New Delhi had reportedly raised the issue of delayed S-400 deliveries under the previous contract ahead of the India-Russia Annual Summit. The deal had been signed in October 2018 — in spite of a warning by the US that going ahead with the contract may invite sanctions under the provisions of the Countering America’s Adversaries Through Sanctions Act.
The ongoing S-400 air defence deliveries and potential new procurement talks may also feature as Putin makes a fresh visit to New Delhi later this year. Prime Minister Narendra Modi is incidentally slated to hold bilateral talks with his Russian counterpart today. The duo will meet on the sidelines of the Shanghai Cooperation Organisation Summit in Kyrgyzstan.
Geopolitical implications
The deal also holds significant political implications amid the Ukraine war — with the United States continuing to voice its objections and issue warnings to India. A second agreement to double the S-400 fleet also comes at a time when New Delhi is staring at the possibility of 100% tariffs for its continued purchase of Russian oil and gas.
US officials have warned of sanctions under the Countering America’s Adversaries Through Sanctions Act since the first agreement was signed in 2018. Punitive actions could include operational and logistical delays or cancellation of existing foreign military sales contracts.
The heavy reliance on Russian technology also creates concerns about long-term technological sovereignty. Global sanctions and a lengthy war with Ukraine have already delayed the delivery of spare parts and replacement missile rounds with proprietary components. It also leaves India reliant on Russian OEM software updates for any vulnerabilities that may crop up.