China has agreed to buy a large number of S-300 anti-aircraft missile systems from Russia, Interfax reported on Friday, citing the director of the Russian plant that makes the weapons.
The truck-mounted S-300, known in the West as the SA-20, can shoot down cruise missiles and aircraft.
Interfax quoted Igor Ashurbeili, director general of Almaz Antei, as saying China would receive a total of 15 batteries of S-300s. He did not give the value of the deal.
In Russia's armed forces, a S-300 battery normally consists of four truck-mounted installations, each consisting of four missiles held in metal tubes.
Moscow has said it plans to fulfil a contract to supply the S-300, nicknamed "the favorite" in Russia, to Iran, unnerving Israel and its close ally the United States.
The possible sale to Tehran of the S-300, which could protect Iran's nuclear facilities against air strikes, has become a sensitive issue in Russia's relations with Israel.