Updated

Russia's intelligence service said Wednesday it has detained an alleged Chinese spy who tried to obtain designs of an advanced missile system as part of Beijing's efforts to update its weaponry.

The Chinese national, who worked as an interpreter for visiting Chinese officials, made attempts to buy documentation for the S-300 long-range surface-to-air missile system, the Federal Security Service said in a statement.

Prosecutors submitted the case to the Moscow City Court Wednesday, although the man was detained late last October, it said.

The truck-mounted S-300 is capable of shooting down aircraft, cruise missiles and ballistic missile warheads at ranges of over 90 miles and at altitudes of about 90,000 feet.

In recent years, Russia banned the sale of the S-300 systems to Iran and Syria following international pressure.

Beijing has for decades been a No. 1 buyer of Russian weapons, including aircraft and submarines. Chinese developers often combine old Soviet platforms with new Chinese technology.