Russia secretly helping Iran build supersonic cruise missiles, reveals investigation

Russia is secretly assisting Iran in developing advanced supersonic cruise missiles capable of threatening US aircraft carriers and other warships in the Middle East, according to a Financial Times investigation.

The multiyear covert program, codenamed C430L, began in 2023 and has involved some of Russia’s most experienced missile specialists.

It continued into the period of the US-‘Israeli’ conflict with Iran. The FT uncovered details through leaked Russian correspondence, travel records, and analysis of military patents, describing the effort as one of the most significant known transfers of strategic military technology from Moscow to Tehran.

At the core of C430L is assistance with a ramjet propulsion system—an engine that enables a cruise missile to sustain flight at several times the speed of sound.

Experts say the technology is almost certainly intended for anti-ship and land-attack cruise missiles.

Supersonic cruise missiles combine high speed with low-altitude flight, sharply reducing the time available for air and missile defenses to detect and intercept them.

“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, an expert on Iranian missiles and senior analyst with Conflict Armament Research.

“A programme like this would require political clearance from the very top in Russia.” Hinz noted that only a small number of countries possess the technical knowledge for a functioning ramjet-based weapon and that Russia has long focused on the technology.

Jim Lamson, a former CIA military analyst focused on Iran who is now at the James Martin Center for Nonproliferation Studies, said the capability would represent a major advance: “For the Iranians, this would give them a qualitatively new strategic weapon system that could threaten US Navy vessels.”

He added that successful Russian help fixing technical problems would rank among the more impactful areas of recent military-technical assistance to Iran, with long-term benefits for its defense industry.

Russia’s state arms exporter Rosoboronexport arranged the program in coordination with NPO Mashinostroyenia, a major Russian rocket design bureau sanctioned by the United States since 2014 for work on cruise missiles and strategic systems.

Leaked travel records show Russian officials and senior NPO Mashinostroyenia engineers made repeated trips to Iran before the contract was formally signed with Iran’s Ministry of Defence and Armed Forces Logistics in November 2023.

By 2025, the Russian side had received Iranian technical materials on the ramjet system, analyzed flight-test data, and provided detailed questions and guidance on aspects such as fuel systems, combustion stability, air intakes, and nozzles.

Discussions of a further phase continued into 2026.

Iran has built and flight-tested a ramjet propulsion system, according to the reporting, though there is no evidence that a Russian-assisted supersonic cruise missile has entered operational service.