India Eyes 5 More S-400 Systems After Operation Sindoor; Russia Sends Cost Proposal

India’s plan to acquire five additional S-400 Triumf air defence systems from Russia has moved forward, with Moscow sending New Delhi a Bill of Quantities (BOQ) proposal detailing construction and material costs to facilitate negotiations on the final price.

The fifth and final S-400 system under the $5.43 billion contract signed by the Narendra Modi government in 2018 is expected to arrive in India in November this year.

However, contrary to some media reports, India has not yet taken a decision to acquire two squadrons of Russia’s fifth-generation Su-57 fighter jets. The Indian Air Force has, however, expressed interest in Moscow’s proposal amid concerns over China’s deployment of its J-20 fifth-generation fighters at airbases in Tibet, including Hotan, Lhasa and Nyingchi, under the PLA’s Western Theatre Command.

According to sources, a decision on acquiring five more S-400 squadrons will be taken by the Cabinet Committee on Security after the cost negotiations with Russia are concluded and the Finance Ministry provides clearance. The additional S-400 system is expected to strengthen India’s eastern sector facing China.

The S-400 system also played a significant role during Operation Sindoor in May 2025, according to Indian defence sources. One of its long-range missiles reportedly engaged a Pakistani airborne early warning aircraft at a distance of 314 kilometres inside Pakistani territory.

Pakistan also used kamikaze drones in attempts to target S-400 systems deployed at the Adampur and Bhuj air bases. Indian officials have maintained that the air defence system deterred Pakistani fighter aircraft from approaching Indian airspace.

On May 10, Pakistan reportedly relocated several air assets to bases near the Durand Line after Indian strikes hit multiple Pakistani air bases. Indian defence claims also said Pakistani fighter aircraft were brought down by India’s S-400 and Akash-Tir air defence systems.

Meanwhile, with Russian President Vladimir Putin expected to visit New Delhi for the BRICS summit from September 11 to 13, India and Russia are also expected to further strengthen defence cooperation, including in the hypersonic missile sector.