"Reports on deliveries of S-300 systems are untrue," the statement said.
Iran's official news agency IRNA, quoting a deputy head of Iran's parliamentary foreign policy and security commission, reported on Sunday that Russia had started supplying components for S-300 surface-to-air missile systems.
Russia's state-run arms exporter said earlier on Monday that Moscow only sold defensive weapons to Iran, in strict compliance with the international nonproliferation regime.
"Only defensive systems are being supplied to Iran, including surface-to-air systems. Previously, Tor-M1 air-defense systems were supplied to Iran," Rosoboronexport said.
Iran's Foreign Ministry has neither denied nor confirmed the report.
An Israeli Foreign Ministry spokesman said Tel Aviv had received assurances from Russia that it had not started S-300 deliveries to Tehran.
A deputy chief of Russia's federal service for military cooperation said last Wednesday that military cooperation between Russia and Iran was designed to ensure regional stability.
"Military cooperation between Russia and Iran has a positive impact on stability in the region. We have been developing and will continue to develop this cooperation," Alexander Fomin said.
According to unofficial sources, Russia and Iran are currently in talks on a deal to sell Tehran advanced medium-range surface-to-air missile systems.