Russia and Iran’s rapidly expanding defence partnership has taken a dramatic new turn, with newly leaked Russian military-industrial correspondence confirming that Moscow has already begun production of the first batch of 16 Su-35 multirole fighters destined for Tehran. The documents, which surfaced in late November 2025, show that assembly is underway at the Komsomolsk-on-Amur Aviation Plant (KnAAZ), with full delivery of the first tranche expected by the end of 2027.
The leak provides the clearest evidence to date that Russia is moving ahead with Tehran’s massive €6 billion (US$6.5 billion) order for 48 Su-35s—one of the largest bilateral fighter-jet transfers in the post–Cold War era. Analysts warn the acquisition could alter regional air-power balances, reshape the Middle East’s strategic calculus, and complicate planning for Israel, Saudi Arabia, and the United States.
The breach has been attributed to Ukrainian cyber operatives who reportedly penetrated Russian defence contractors in late November, revealing detailed internal correspondence on export-grade Su-35 production for Iran. Russian authorities have remained silent—consistent with past incidents where classified defence programmes were involuntarily exposed.
The documents indicate that production of Iran’s first 16 aircraft quietly began in 2024, supervised by Russian Defence Ministry officials responsible for avionics integration and export-compliance inspections. KnAAZ, Russia’s premier Sukhoi production facility, historically manufactures around 14 Su-35s annually, but internal directives suggest the plant has been instructed to increase output to meet several high-priority foreign orders.
The November disclosures follow a separate October 2025 leak from Concern Radio-Electronic Technologies (KRET), which unveiled Iran’s procurement of advanced avionics, Khibiny-M electronic warfare pods, radar-warning systems, and cockpit displays—items bundled within the €6 billion Su-35 package. The KRET documents identified Iran under the internal customer code “364,” with deliveries of the full 48 aircraft planned between 2026 and 2028.
Open-source intelligence analysts reviewing both leak sets report high consistency in supplier codes, contract timelines, and documentation formats, reinforcing confidence in the authenticity of the disclosures.
Iran’s combat aviation fleet is among the oldest in the world. Much of the Islamic Republic of Iran Air Force (IRIAF) continues to rely on 1960s- and 1970s-era American aircraft—including F-4 Phantoms, F-5 Tigers, and F-14 Tomcats—along with ageing Soviet-era MiG-29s and Su-24s. Chronic sanctions, spare-parts shortages, and maintenance cannibalization have severely eroded readiness levels.
Domestic upgrade projects such as the Kowsar and Saeqeh have delivered only limited performance improvements, falling far short of modern fourth-generation standards. The Su-35 acquisition, therefore, represents Iran’s most significant aviation modernization in more than four decades.
The deal’s roots trace back to intensified Russia–Iran military consultations beginning in 2019 and accelerating after Russia’s 2022 invasion of Ukraine, when Iran supplied Moscow with drones. Initial speculation suggested that Iran might receive Su-35s originally built for Egypt, but the newly leaked documents confirm that fully new construction is underway at KnAAZ.
Satellite imagery captured through 2024–2025 shows major upgrades at Iran’s Tactical Air Base No. 8 in Isfahan, hinting at preparations for hosting advanced Russian fighters. Reports also suggest that Russian aviation advisers have been stationed in Iran since early 2024 to support infrastructure improvements, training pathways, and potential semi-knocked-down assembly cooperation with Iran’s Aviation Industries Organization (IAIO).
Widely regarded as one of the world’s most capable non-stealth fighters, the twin-engine Su-35S boasts exceptional manoeuvrability, high-performance avionics, and sophisticated electronic warfare capabilities.
Irbis-E radar capable of detecting targets at over 350 km
Ability to track 30 targets and engage eight simultaneously
AL-41F1S engines with 3D thrust-vectoring, enabling supermaneuverability
Combat radius exceeding 1,500 km, extendable to 3,600 km with external fuel
Compatibility with R-77-1, R-37M long-range missiles, and Kh-59MK2 precision strike weapons
Khibiny-M EW pods providing radar-jamming and missile-spoofing capabilities
For Iran, these attributes represent a transformational leap that would allow the IRIAF to conduct long-range defensive and offensive missions across the Gulf, Levant, Red Sea, and Arabian Sea.
Defence observers say the deal cements a deepening Russia–Iran defence axis shaped by shared hostility to Western sanctions and geopolitical pressure. The acquisition follows Iran’s humiliating performance during the June 2025 Israeli-Western air assault on Iranian infrastructure, when the IRIAF’s obsolete fleet had limited impact.
Once operational, two Su-35 squadrons would significantly strengthen Iran’s ability to deter pre-emptive strikes on its nuclear sites, challenge GCC air forces, and sustain power projection in Syria, Iraq, and the Gulf.
Israel views the transfer as a strategic threat and has already begun simulating Su-35–versus–F-35I engagements to identify vulnerabilities in the Iranian configuration. Saudi Arabia and the UAE are expected to accelerate purchases of F-15EX jets, Eurofighter upgrades, and advanced missile-defence systems.
The United States has condemned the deal as destabilizing and is preparing sanctions targeting Russian defence suppliers and Iranian procurement networks.
