Russia's Interfax news agency cites a top military official as saying the UN's latest Iran sanctions, which Moscow has backed, rule out the delivery of missile systems.
Russia has yet to fulfill a 2007 contract with Iran over the delivery of the sophisticated S-300 defense missiles. The West has urged against arming a state suspected of running a covert nuclear weapons program.
Military official Alexander Fomin on Tuesday did not directly identify the S-300s, but pledged Moscow would desist from supplying "large missile systems" in accordance with the sanctions, Interfax reported.
It is the latest indication that the deal is dead. Last month, the Russian government said the sanctions blocked the missile sale, but Iran insisted the restrictions don't cover existing contracts.