Russia has begun air defence exercises in the Ural mountains and western Siberia involving 12,000 soldiers and 250 aircraft, the defence ministry said on Tuesday.
The manoeuvres, which began on Monday and are to last until Thursday, are meant to help the military prepare for a larger drill in September, called Tsentr-2015.
After Russia's annexation of Ukraine's Crimea region in March 2014, Russia has held numerous large-scale military drills checking combat readiness.
The focus of the drills, the ministry said in a statement on its website, is on developing a command system in field conditions as well as setting up all-round aviation security measures in new base areas.
The drills in the Central Military District have been reinforced by units from the Western and Southern military districts, the ministry added, as well as long-range aircraft.