Russia Begins Building 16 Su-35 Fighters for Iran Under US$6.5 billion Deal, Leak Confirms Full Delivery by 2027

(DEFENCE SECURITY ASIA) — In a dramatic escalation of Russia–Iran defence cooperation that is sending powerful ripples across global military circles, newly leaked Russian defence correspondence confirms that Moscow has already begun production of the first batch of 16 Su-35 multirole fighters destined for Iran.

The documents, which surfaced in late November 2025, indicate that assembly is currently underway at the Komsomolsk-on-Amur Aviation Plant (KnAAZ), Russia’s premier manufacturing hub for advanced Sukhoi fighters, with full delivery scheduled for completion before the end of 2027.

The leak reinforces an earlier October 2025 revelation that Iran had agreed to a massive €6 billion (approximately US$6.5 billion / RM30.5 billion) deal covering a total of 48 Su-35 aircraft in one of the largest bilateral arms transfers seen between Moscow and Tehran in modern history.

This latest disclosure has triggered intense debate within global defence and intelligence circles, with analysts warning that the arrival of these fourth++-generation fighters could transform the Middle Eastern airpower balance and ultimately reshape strategic competition involving Israel, Saudi Arabia, the United States, and other regional powers.

The breach—attributed to Ukrainian hackers penetrating Russian military-industrial networks—has renewed scrutiny of Moscow and Tehran’s deepening strategic alignment under the pressure of Western sanctions, energy competition, proxy conflicts, and shared geopolitical adversaries.

These Su-35 acquisitions represent the most significant modernization of Iran’s manned combat aviation in more than four decades, positioning Tehran to replace its ageing Vietnam-era fleet with one of the world’s most capable non-stealth fighter platforms.

The disclosures arrive at a time when Russia’s aerospace industry is sharply increasing output to meet wartime domestic demand while simultaneously catering to high-priority clients like Iran, Algeria, Ethiopia, and others seeking to break out of Western military supply chains.

The Latest Leak: Production Details, Origins, and the Expanding Paper Trail

The newly surfaced Russian correspondence, leaked on November 28, 2025, provides unprecedented insight into the production progress of the first 16 Su-35s intended specifically for the Iranian Defence Ministry.

According to the documents, manufacturing of these aircraft began in 2024, with teams of Russian Ministry of Defence officials overseeing subsystem integration and quality assurance for export compliance.

The Komsomolsk-on-Amur Aviation Plant—responsible for nearly all Su-35 export production—has historically maintained an output of roughly 14 aircraft per year, though recent internal directives and infrastructure investments signal an intention to push this capacity higher.

UAC leadership had already confirmed in mid-2025 that KnAAZ was undergoing expansion to meet “several major international orders,” a statement now understood to have been referencing the Iran contract.

The November leaks follow an earlier October 2025 breach at Russia’s Concern Radio-Electronic Technologies (KRET), which exposed Iran’s €6 billion procurement package for 48 aircraft, inclusive of 24 Khibiny-M electronic warfare pods, advanced avionics suites, heads-up display systems, radar-warning receivers, and additional subsystems.

The leaked KRET documentation identified the Iranian customer under the internal code “364,” revealing that the 48-unit procurement would be delivered through phased batches between 2026 and 2028.

OSINT analysts reviewing both leak sets note consistent supplier codes, common procurement timelines, and identical export documentation patterns seen in previous Russian fighter transfers, further increasing confidence in the authenticity of the disclosures.

Russian authorities have maintained silence, a familiar posture adopted in previous incidents where sensitive export programmes were unintentionally exposed.

Cybersecurity specialists believe the leaks were intended to undermine deepening Russia–Iran military cooperation by triggering diplomatic and intelligence blowback from Western powers already concerned about Iran’s expanding advanced weapons ecosystem.

Iran’s Quest for Air Superiority and the Long Road to Modern Combat Aviation

Iran’s pursuit of modern fighter jets is rooted in more than forty years of sanctions, attrition, and persistent operational degradation across its ageing fleet.

The Islamic Republic of Iran Air Force (IRIAF) currently fields approximately 300 aircraft, many of which—including F-4 Phantoms, F-5 Tigers, F-14 Tomcats, MiG-29s, and Su-24s—are relics of the 1960s and 1970s.

These aircraft suffer from severe maintenance constraints, avionics obsolescence, and chronic spare-parts shortages, often forcing Iranian engineers to cannibalize grounded airframes to keep others flying.

Local attempts to domestically modernize these jets, such as the Saeqeh and Kowsar programmes, have failed to deliver true fourth-generation capabilities, leaving Iran with only limited stopgap improvements.

Negotiations with Russia for the acquisition or local assembly of MiG-29s and Su-27s date back to the 1990s but were halted due to Western pressure and Russia’s adherence to international arms embargoes until 2020.

The Su-35 deal’s origins, however, can be traced to 2019, when Tehran and Moscow began deeper military consultations that intensified further in 2022 following Russia’s full-scale invasion of Ukraine and Iran’s supply of drones to Russia.

Initial assessments in 2022–2023 indicated Iran might receive 24–25 Su-35s originally intended for Egypt before the U.S. intervened to block Cairo’s acquisition.

Conflicting Iranian statements throughout 2024 created uncertainty, but in January 2025, a senior IRGC aerospace commander publicly confirmed the existence of a major Su-35 purchase agreement.

Satellite imagery captured throughout 2024 and early 2025 revealed major infrastructure upgrades at Tactical Air Base No. 8 (TAB-8) in Isfahan, strongly suggesting preparation for a new generation of Russian-built fighters.

Additional reports indicate Russian aviation advisors have been quietly deployed to Iran since early 2024 to assist with airbase upgrades, pilot training pathways, and potential semi-knocked-down (SKD) assembly options involving Iran’s Aviation Industries Organization (IAIO).

If confirmed, Iran could replicate elements of the India–Russia Su-30MKI co-production model, enabling limited domestic assembly and long-term sustainment independence, a strategic priority driven by Tehran’s exposure to sanctions-induced supply disruptions.

Production Status, Delivery Timeline, and Financing Mechanisms Behind the Deal

The leaked correspondence states that the first 16 Su-35s are being tailored to Iranian mission requirements and may incorporate modifications aligned with the forthcoming Su-35SM standard.

Production at KnAAZ has been designated a high-priority project, with regular inspections by Russian defence officials ensuring that export-grade avionics, radars, and EW suites meet agreed configurations.

Deliveries for the 16-aircraft batch are expected between 2026 and 2027, aligning with the broader 48-unit schedule extending into 2028.

Russia’s ability to meet these deadlines is being tested by dual pressures: the demands of wartime aircraft replacement for its own forces and sanctions-driven shortages of aviation microelectronics and flight avionics.

Despite these constraints, the expansion of KnAAZ facilities and the involvement of multiple subcontractors indicate Moscow’s determination to honour this strategically significant contract.

Iran’s financing method for the deal likely involves a combination of oil-for-arms barter arrangements, drone-technology transfers, and alternative payments designed to bypass Western-controlled financial systems.

Such arrangements are consistent with previously observed Russia–Iran industrial cooperation models and allow both nations to circumvent banking sanctions by replacing currency-based transactions with commodity-based exchanges.

Logistical delivery routes may rely on the Caspian Sea corridor—specifically the Astrakhan–Anzali route—where sanctions enforcement is weakest and Russian naval escorts can provide protection against interdiction.

Alternatively, Russia may utilize An-124 or Il-76 strategic airlifters for high-value subsystem deliveries and personnel transfers to expedite integration within Iran.

Analysts also warn that regional intelligence agencies may attempt to disrupt components of the transfer through targeted sabotage, cyber operations, or maritime interception attempts, given the transformative potential of the Su-35 for Iran’s airpower.

Technical Capabilities of the Su-35: A Strategic Force Multiplier for Iran

The Sukhoi Su-35S, NATO-designated “Flanker-E,” is widely regarded as one of the most capable non-stealth fighters in the world, offering a formidable combination of long-range sensors, high-energy manoeuvrability, and advanced EW survivability suites.

Powered by twin Saturn AL-41F1S engines with 3D thrust-vectoring capability, the aircraft achieves speeds of Mach 2.25 and supports sustained supermaneuverability unmatched by most Western fourth-generation fighters.

Its combat radius exceeds 1,500 km, extendable to 3,600 km with additional fuel tanks, enabling Iran to project airpower across the Persian Gulf, the Arabian Sea, Iraq, Syria, Lebanon, and even deep into the Red Sea if required.

The Irbis-E PESA radar is capable of detecting targets at more than 350 km, tracking up to 30 simultaneously, and engaging eight concurrently, giving the Su-35 a major beyond-visual-range (BVR) advantage over Iran’s current fleet.

For Iran, the aircraft’s compatibility with R-77-1 medium-range missiles, R-37M hypersonic long-range missiles, and Kh-59MK2 precision strike weapons dramatically expands the IRIAF’s ability to threaten adversary airbases, naval vessels, and critical infrastructure from standoff distances.

The inclusion of Khibiny-M electronic warfare pods provides missile-spoofing, radar-jamming, and electronic deception capabilities essential for penetrating the integrated air-defence networks of Israel or Saudi Arabia.

Strategically, pairing Su-35 squadrons with Russia’s S-400 air-defence systems—also believed to be part of Iran’s procurement pipeline—would create a layered A2/AD (anti-access/area-denial) network that would complicate Israeli or American strike planning.

The aircraft’s high-altitude performance, supercruise capability, and endurance make it ideal for combat air patrols defending Iran’s nuclear facilities, energy infrastructure, and forward bases supporting regional proxy operations.

Iran may also request customizations, including integration of domestic munitions, strengthening of EW features to counter F-35I Adir operations, or enhancements to withstand intense GPS jamming and electronic warfare environments prevalent in the Persian Gulf.

Geopolitical Ramifications: A Paradigm Shift in Middle Eastern Airpower

The Su-35 deal reinforces a strategic Russia–Iran defence axis that has grown stronger in response to Western sanctions, proxy warfare, and pressure campaigns designed to constrain both nations’ geopolitical influence.

Iran’s new Su-35 fleet directly addresses vulnerabilities exposed during the June 2025 Israeli-Western air assault on Iranian infrastructure, during which the IRIAF contributed only marginally due to ageing aircraft and limited operational reach.

The collapse of the Syrian government in December 2024 further emphasized Iran’s dependence on drones and missiles, exposing the IRIAF’s inability to sustain air dominance over contested territories.

Armed with 48 Su-35s, Iran could field two modern high-capability squadrons capable of deterring Israeli pre-emptive strikes, countering Gulf Cooperation Council (GCC) fighter fleets, and projecting power across multiple theatres simultaneously.

Saudi Arabia and the UAE are expected to accelerate acquisitions of Eurofighter Typhoon variants, F-15EX platforms, or enhanced air-defence architectures in response, intensifying a regional arms race already pushing Middle Eastern defence spending toward US$190 billion / RM892 billion annually by 2026.

Israel views the Su-35 transfer as a strategic red line and has already begun simulating Su-35 vs. F-35I engagements to study potential weaknesses in the Iranian configuration.

The United States has publicly condemned the deal as destabilizing and is weighing new sanctions targeting Russia’s defence-industrial partners and Iranian procurement networks.

Globally, the deal signifies a growing multipolarity where Western defence ecosystems are increasingly challenged by alternative blocs led by Russia, China, and sanctioned states forming mutually reinforcing military supply chains.

Western air dominance—long anchored by the F-15, F-16, F-18, and fifth-generation F-35 fleets—is being tested by new export pathways that place advanced fighters in the hands of nations traditionally denied access to Western systems.

— DEFENCE SECURITY ASIA