MOSCOW, Aug. 19 (Xinhua) -- Russian President Dmitry Medvedev and his Belarusian counterpart Alexander Lukashenko have agreed to sign an agreement this fall to set up a joint air defense system, a Russian presidential aide said.

　　At a meeting in the Black Sea resort of Sochi on Tuesday, the presidents agreed to hold a regular meeting of the Supreme State Council of the Russia-Belarus union in Moscow this fall, when "an agreement on building a unified air defense system will be signed," a Kremlin aide was quoted by the RIA news agency as saying.

　　Medvedev and Lukashenko also discussed "some practical issues of bilateral trade and economic cooperation," the aide said, noting that bilateral trade between the two nations could reach 30billion U.S. dollars this year.

　　Moscow and Minsk are developing a unified air defense system in accordance with plans to create a Union State, which they have been working on since 1997, envisioning a common economic, customs, and political space.

　　Although talks on the Union State have been held up recently over a series of issues, military cooperation between the two sides have been gaining momentum, spurred by U.S. plans to deploy a missile defense system in Poland and the Czech Republic.