Russia has been secretly helping Iran develop advanced supersonic cruise missiles through a multiyear covert programme codenamed C430L, according to a Financial Times investigation. The programme, which began in 2023, enlists Russian missile specialists to help Iran develop a ramjet propulsion system capable of sustaining flight at several times the speed of sound. "This is the transfer of a highly strategically sensitive military technology from Russia that the Iranians have wanted to acquire for decades," said Fabian Hinz, senior analyst with Conflict Armament Research. The technology is intended for anti-ship and land-attack cruise missiles, potentially threatening US aircraft carriers in the Middle East.

An FT investigation uncovered the programme through leaked Russian correspondence, travel records and military patents. The project was arranged by Rosoboronexport with NPO Mashinostroyenia, a company sanctioned by the US in 2014 for cruise missile work. Experts say this deeper cooperation shows Russia is trying to broaden the Ukraine war and draw the US into different theatres, with Moscow reportedly providing satellite imagery, drone support and weapons components to Iran during its conflict with the US and Israel.