For years, defense analysts and geopolitical observers have speculated about the deepening military ties between Moscow and Tehran, but a massive cache of internal documents leaked by United24 on November 28, 2025, has finally moved the conversation from conjecture to hard evidence. The revealed correspondence from the Russian military-industrial complex offers an unprecedented look into a covert production line that is currently churning out advanced Su-35 fighter jets specifically for the Iranian Air Force. According to these documents, despite the immense strain the war in Ukraine has placed on Russia’s own aerospace sector, the Kremlin is prioritizing the delivery of 16 new Flanker-E fighters to Iran between 2025 and 2027, a move that threatens to fundamentally alter the balance of air power in the Middle East.
The leaked papers paint a picture of a sophisticated, hurried, and strictly controlled manufacturing process. The correspondence identifies the foreign customer simply as “K10,” though in a slip of operational security, at least one letter explicitly names Iran as the destination. The production is centered at the Yuri Gagarin Komsomolsk-on-Amur Aviation Plant, Russia’s premier fighter jet facility, but the supply chain stretches across the country. Specific orders show that the Zvezda facility is rushing to finalize K-36 ejection seats, while the Second Moscow Instrument-Making Plant is tasked with delivering critical sensor suites. What stands out in the technical requirements is the stipulation that all cockpit labeling and technical manuals must be in English using the Anglo-Saxon measurement system. This confirms the aircraft are in a specific export configuration, designated to bridge the gap for Iranian pilots transitioning from their aging American-made platforms to modern Russian avionics.
Financially, the deal appears to be solid and fully active. The documents record a series of prepayments made throughout 2024—specifically in March, July, and December—indicating that Tehran has already put significant capital down to secure these airframes. This financial commitment seemingly guaranteed that work began on the jets as early as 2024. The timeline is aggressive; even as Russia loses aircraft in its own conflicts, the Ministry of Defense has assigned specific units, such as Unit 2311 and Unit 703, to oversee quality assurance for this export contract. The goal is clear: to have a fully operational squadron of these heavy fighters ready to fly within a two-year window.
For Iran, this acquisition is nothing short of a generational leap. For decades, the Islamic Republic of Iran Air Force has been held together by the ingenuity of its engineers, who have kept a heterogeneous mix of pre-revolutionary F-14 Tomcats and F-4 Phantoms flying alongside 1990s-era MiG-29s. While Iran has managed to domesticate some parts production and even reverse-engineer older technology, the capability gap between them and their regional rivals has widened into a chasm. The limitations of this vintage fleet were laid bare during a recent twelve-day flare-up with Israel, where Iranian fighters struggled to maintain persistent patrols or effectively counter fifth-generation threats. The arrival of the Su-35 is intended to plug this hole. With a combat radius exceeding 2,000 kilometers and the ability to carry the dreaded R-37M air-to-air missile, which boasts a range of nearly 400 kilometers, the Su-35 allows Iran to push its defensive perimeter far out into the Persian Gulf and the Strait of Hormuz.
The logistics of getting these massive machines into Iran are already in motion. Reports indicate that the first two Su-35SE fighters were handed over in November 2024, transported in a disassembled state aboard giant An-124 cargo planes to Tehran before being shuttled to the 3rd Tactical Air Base near Hamadan for reassembly. The strategic plan revealed in the leaks suggests a dual-basing arrangement: the 81st Tactical Fighter Squadron in Isfahan will receive jets to replace the legendary but weary F-14s, while the 31st Tactical Fighter Squadron in Hamadan will trade its F-4 Phantoms for the new Russian jets. The ambition doesn’t stop at direct imports; there are indications that Tehran has secured a license to potentially produce dozens more of these aircraft domestically, though international observers remain skeptical about Iran’s industrial capacity to handle such high-tech fabrication without significant Russian assistance.
This transfer of technology represents the culmination of a rapidly evolving symbiotic relationship. While Russia was once the senior partner, supplying 85 percent of Iran’s arms in the early 2000s, the dynamic has shifted toward mutual dependence. Moscow needs Iranian Shahed drones and ballistic missiles to sustain its operations in Ukraine, while Tehran needs advanced fighter jets to modernize its air force and protect its nuclear infrastructure. This “reciprocal flow of capabilities” has solidified into a comprehensive strategic partnership. We are now seeing Russian electronic warfare systems, like the Murmansk-BN, and armored vehicles appearing in Iran, while Iranian pilots have been training on Yak-130 advanced jet trainers since late 2023 to prepare for the leap to the Su-35’s digital cockpit.
The Su-35 itself is a formidable machine that brings capabilities Iran has never possessed. It is a deep modernization of the Soviet-era Su-27, featuring thrust-vectoring engines that allow for post-stall maneuvers—essentially enabling the plane to turn on a dime during a dogfight. However, its real value to Iran lies in its radar and standoff capabilities. The Irbis-E radar can track up to 30 targets simultaneously, giving Iranian commanders a much clearer picture of the airspace than their current ground-controlled interception methods allow. Furthermore, Iran has been hardening its infrastructure to ensure these expensive assets aren’t destroyed on the ground. The construction of the Eagle 44 underground air base and reinforced hangars at Hamadan suggests that Tehran is preparing for a long-term strategy of deterrence, protecting their new fleet from preemptive strikes by Israel or the United States.
As these 16 jets move through the assembly lines in Komsomolsk-on-Amur, the geopolitical ripples are already being felt. Russia’s ability to export arms has plummeted globally, leaving it reliant on a few key partners like Iran and Algeria to keep its production lines warm and currency flowing. By fulfilling this contract despite its own wartime shortages, the Kremlin is sending a signal that it remains a major player in Middle Eastern security architecture. For the pilots of the Iranian Air Force, who have spent their careers nursing forty-year-old airframes into the sky, the arrival of the Su-35 marks the end of an era of scarcity and the beginning of a new, more capable, and potentially more volatile chapter in regional air power.
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