Kaliningrad Special Region (Russian: Калининградский особый район) (also known as the Kaliningrad Defensive Area (Russian: Калининградский оборонительный район)) (Russian: КОР) was a military district of the Russian Armed Forces from 1997 to 2010. It was charged with the defense of the Kaliningrad Oblast and protection of national interests in the southern Baltic. The area of the KDA was unique in Russia, as separate branches of the armed forces existed under a single command. In recent years, the Kaliningrad Special Region played an important role in countering the U.S. missile defense system in Europe. On September 1, 2010, the district was merged with the Leningrad and Moscow military districts to create the Western Military District.