Units from a joint air defense system of the Commonwealth of Independent States (CIS) are conducting exercises with live firing drills on September 6-12, the Russian Defense Ministry said on Thursday. The drills at the Ashuluk firing range in the Astrakhan Region near the Caspian Sea are part of the Combat Commonwealth 2011 air defense exercises. \"About 30 aircraft, including four MiG-29 fighter jets from Belarus, take part in the exercises,\" Air Force spokesman Col. Vladimir Drik said. Air defense units from Armenia, Kyrgyzstan and Tajikistan, equipped with S-200, S-125, Buk and other systems, also participate. The drills include airstrikes on ground targets, simulated \"dog fights\" and interception of aerial targets. Conducted annually, Combat Commonwealth exercises are part of efforts to build a joint air defense shield for the CIS, a loose association of former Soviet republics. An integrated air defense network was set up by 10 CIS-member countries February 10, 1995. The main purpose of the network is to ensure the protection of the member-countries\' airspace, early warning of missile attacks and coordination of joint efforts to neutralize potential air threats. The CIS network currently comprises seven air defense brigades, 46 units equipped with S-200 and S-300 air defense missile systems, 23 fighter units equipped with MiG-29, MiG-31 and Su-27 aircraft, 22 electronic support units and two detachments of electronic warfare.