MOSCOW, September 14 (RIA Novosti) - A train carrying Belarusian S-300 air defense systems has arrived at the Ashuluk training grounds in southern Russia to participate in Zapad-2009 strategic drills, the Russian Defense Ministry said on Monday.

The joint Russian-Belarus exercise on September 8-29 involves 12,500 personnel and a large number of tanks, armored vehicles, artillery pieces, air defense systems and aircraft.

The exercise will, among other things, rehearse interoperability within the framework of the Belarusian-Russian integrated air defense system, which the two countries agreed to establish in February.

S-300s are considered one of the world's most effective all-altitude regional air defense systems, comparable in performance to the U.S. MIM-104 Patriot system.

Belarus has several Russian-made S-300 air defense battalions on combat duty, and has long been negotiating the purchase of advanced S-400 systems from Russia, which should be available in 2010.

(Russian mobile surface-to-air missile systems - Image gallery)