Russia's customs service said Thursday it uncovered a ring of active and retired military officers suspected of involvement in stealing millions of dollars worth of missile components and smuggling them out of Russia.

The Federal Customs Service said it has detained a dozen suspects and confiscated about 22 tons of missile components intended for smuggling.

It said in a statement Thursday that the criminal ring had smuggled parts of S-75, S-125, S-200 and S-300 air defense missile systems to Russia's ex-Soviet neighbors of Belarus, Kazakhstan and Ukraine and also to Bulgaria. The statement said the alleged criminal group had been smuggling missile parts for at least two years.

The state-run Channel One television cited the customs as saying that the suspects had stolen missile parts worth hundreds of millions of dollars.

The customs service said it recently had intercepted two shipments of missile systems components on Russia's borders with Ukraine and Belarus, including a radar and other parts.

The customs agency said that the ring included Russian military officers on active duty along with some retirees and citizens of Belarus and Ukraine. It said the suspects were believed to work with senior officers of the military's air defense forces stationed in Russia's northwest, but would not give any names.

The S-300 is a state-of-the art missile system capable of shooting down aircraft and missile warheads at long ranges. Russia's plans to sell S-300s to Iran have caused concern in the United States and Israel.

The other types of Soviet-designed air defense missile systems mentioned by the customs agency date back to the 1960s and the 1970s, but they remain efficient and have remained in service with many militaries around the world.