India eyes Russia S-400 deal despite US sanctions threat

Russian President Vladimir Putin is in India amid growing unease in India–US relations and the stalled 2025 Quad summit. Although the trip, from December 4-5, falls under the India-Russia annual dialogue mechanism, expectations are high over potential defense outcomes, particularly whether New Delhi will seek additional S-400 air defense regiments.

India purchased five S-400 regiments for about US$5 billion in 2018 and is now considering five more following the system’s reported success during this year’s Operation Sindoor against Pakistan.

Indian Defense Secretary Rajesh Kumar Singh has said further acquisitions “cannot be ruled out” but cautioned against expecting an announcement during Putin’s visit.

During the May 7-10, 2025 India-Pakistan conflict, the S-400 demonstrated high survivability and effectiveness, specifically its “shoot and scoot” capability that helped blunt Pakistani strikes. Indian Air Force Chief A P Singh said the system neutralized five aircraft — including Pakistan’s F-16s — and one large AWACS or SIGINT platform.

He said an S-400 battery also struck a large aircraft more than 300 kilometers inside Pakistan, which he described as the longest-range surface-to-air kill on India’s record. The system’s presence also limited Pakistan’s ability to operate within its own airspace and approach weapons-release ranges.

When Pakistan claimed the S-400 had been destroyed, Prime Minister Narendra Modi underscored its symbolic importance by visiting Adampur base and posing with an operational battery.

India relies on the S-400 as the upper tier of its multilayered air defense network and currently fields three regiments, with two more pending delivery. Even after all five are in service, India will have only 10 batteries — insufficient for its large borders with Pakistan and China and still vulnerable to saturation attacks.

India is developing its own long-range system, known as Project Kusha, with interceptors ranging from 150 to 350 kilometers, but it is not expected to be ready until the 2030s. Until then, additional S-400s remain the only near-term option for strengthening long-range air defense.

Long-Range Surface-to-Air Missile (LRSAM) expansion also helps offset declining fighter squadron strength by shifting some interdiction missions from aircraft to ground-based systems. This approach requires a larger number of long-range batteries, reinforcing India’s interest in expanding its S-400 inventory.

However, any further procurements of the S-400 could complicate already tumultuous ties with the US. US officials have warned further S-400 procurements could trigger sanctions but none have been imposed to date.

In 2020, the US sanctioned Turkey, a fellow NATO member, for its procurement of the S-400, sending bilateral relations in a tailspin. In 2018, the US has also sanctioned China’s Equipment Development Department (EDD) and its director Li Shangfu for “significant” S-400-related transactions.

The system’s appeal is understandable. Russia’s S-400 continues to compare favorably with those of the US Patriot PAC-3. It can track up to 160 targets and engage 72 simultaneously, superior to the PAC-3’s capacity of 125 and 36.

The S-400 can intercept aircraft at 400 kilometers, compared with roughly 180 kilometers for the PAC-3. Its deployment time — about five minutes — also allows rapid relocation, whereas the PAC-3 requires around 25 minutes.

Its radars feature advanced anti-jamming measures, such as agile beam steering and rapid frequency hopping. Attempts by NATO forces and Israel to jam S-400 radars have been reported, but their effectiveness remains unknown.

In conflicts where air superiority shapes outcomes, area-denial systems like the S-400 play a critical role in countering enemy strike capabilities. India’s interest in expanding its S-400 fleet stems from both demonstrated operational performance and the absence of an equally capable domestic or foreign alternative in the near term.

With Russia remaining a willing supplier, additional S-400 regiments would significantly strengthen India’s air defense posture but raise the risk of US sanctions.

Dr Rahul Mishra is an associate professor at the Centre for Indo-Pacific Studies, School of International Studies, Jawaharlal Nehru University, New Delhi, India, and a senior research fellow at the German-Southeast Asian Center of Excellence for Public Policy and Good Governance, Thammasat University, Thailand. He is the series dditor of the Palgrave Series in Indo-Pacific Studies. He can be reached atrahul.seas@gmail.com

Harshit Prajapati is a doctoral candidate at the Centre for Indo-Pacific Studies, School of International Studies, Jawaharlal Nehru University, India. He can be reached at harshi55_isn@jnu.ac.inand followed on X at @harshitp_47