Russia has been secretly supporting Iranian missile development since 2023, according to a report in the Financial Times on Tuesday.
The goal of the program, codenamed C430L, was to help Iran develop missiles capable of taking out US Navy aircraft carriers in the Middle East.
In particular, they aimed to develop a ramjet propulsion system that would allow Iranian missiles to fly at several times the speed of sound.
Fast, low-flying missiles would give Western air defences less time to react increasing the impact of such an attack.
The transfer of advanced missile technology would have required approval from the highest political echelons in Russia, amid speculation that this was a technology exchange. Iran supports Russian drone development, and Russia supports Iranian missile development, in addition to the already existing intelligence cooperation between the two.