Russia has secretly helped Iran develop supersonic cruise missile technology through a covert programme that began in 2023, according to the Financial Times.

Covert programme and technical assistance

The initiative, codenamed C430L, enlisted leading Russian missile specialists to assist Iran in developing ramjet propulsion technology. This technology enables missiles to sustain speeds several times faster than sound. Russia’s state arms exporter Rosoboronexport and missile developer NPO Mashinostroyenia arranged the programme.

Russian engineers made several trips to Iran before a contract was signed with Iran’s Ministry of Defense and Armed Forces Logistics in November 2023. In April 2025, Rosoboronexport proposed sending around two dozen specialists to Iran for technical consultations under C430L. The planned mission focused on analyzing Iran’s propulsion system, with Moscow requesting flight-test telemetry data from Tehran prior to the visit.

Fabian Hinz, an expert on Iranian missiles, described the arrangement as the transfer of highly strategically sensitive military technology that Iran has sought for decades.

Strategic implications

The technology being developed could pose a threat to US warships and other targets. Jim Lamson, a former CIA Iran military analyst at the James Martin Center for Nonproliferation Studies, stated that this would provide Iran with a qualitatively new strategic weapon system capable of threatening US Navy vessels.

Iran has developed and flight-tested a ramjet propulsion system, but there is currently no evidence that a Russian-assisted supersonic cruise missile has been deployed.

Broader military cooperation context

This revelation follows reports of Russia transferring upgraded Shahed-type drones to Iran in March, incorporating battlefield-tested improvements from the Ukraine war. In July, reports emerged of US investigations into whether Russia helped Iran target CIA facilities using advanced drone technology with Kometa-M navigation systems.

President Donald Trump downplayed these reports, stating any Russian assistance had little impact and expressing doubt that Moscow was sharing intelligence with Tehran at a high level. Trump also thanked Chinese President Xi Jinping and Russian President Vladimir Putin for remaining neutral during the conflict with Iran.

Vladimir Putin stated that Ukrainian strikes caused real but non-critical damage to Russia. He quantified the economic impact at 1% of Russia's GDP.

Damage Assessment

Putin dismissed reports of a new mobilisation in Russia as "rubbish". He added that Russia will respond to the attacks.

• Strikes caused real damage to Russian infrastructure.
• Economic loss equals 1% of GDP.
• Putin rejected claims of new military mobilisation.