Leaked documents reveal Russian transfer of sensitive missile technology to Iran

A secret Russian military program allegedly gave Iran access to sensitive technology for developing hypersonic cruise missiles, according to leaked correspondence and documents cited in a Financial Times investigation.

The program, known as C430L, began in 2023 and centers on a ramjet propulsion system. The technology uses a missile’s speed to compress incoming air before fuel combustion, allowing the missile to maintain supersonic speeds throughout its flight. Such missiles could potentially be used against warships and land targets.

The investigation drew on leaked Russian correspondence, travel records and military patents. They reportedly show that the cooperation continued for several years and had reached an advanced stage in 2026, during the war between Iran, the United States and Israel.

The technology is especially important for Iran because, although the country has a large arsenal of conventional ballistic and cruise missiles, it has long faced a technological gap in developing a ramjet-powered supersonic cruise missile.

Iranian missile expert Fabian Hinz described the transfer as a major strategic move for Tehran. He said cooperation of this kind would likely require high-level political approval within Russia. The documents reportedly indicate that Moscow did more than send technical data: they also point to direct collaboration between Russian and Iranian engineers to develop and improve the propulsion system.