Russia has launched its largest military drill of the year, involving 7,000 items of military equipment and some 95,000 infantry, navy and air force units.

“Today the strategic command-and-staff exercise Center–2015 has been started. This is a final stage of the operational and combat training of the Russian Armed Forces in 2015 and joint combat training activities of the CSTO (Collective Security Treaty Organization),” the Russian Defense Ministry announced in a statement on Monday.

Center–2015 is being carried out over 20 sites across Russia’s central military district (marked in light green in the map below), which spans from the Volga River to the Ural mountains and Siberia in the east and reaches to the country’s far northern regions.

According to the statement, the maneuvers’ goal is assessing the readiness of the CSTO, comprised of forces from several ex-Soviet countries, at handling “international armed conflict” and defeating “illegal armed units.”

The extensive exercises, headed by the Russian Armed Forces Chief General Staff Valeriy Gerasimov, are scheduled to come to an end on September 20.

Russia has recently cranked up its snap checks of its military capabilities, assessing its forces from the Arctic to the Far East as relations with the West sharply cooled after Crimea’s reunification with Russia following a referendum in March 2014. Relations were strained further after Ukraine launched military operations in April 2014 to silence pro-Russia protests in the country’s mainly Russian-speaking regions of Donetsk and Luhansk in eastern Ukraine.

Kiev and its Western allies accuse the Kremlin of meddling in Ukraine’s internal affairs and backing pro-Russia forces in eastern Ukraine. Russia has resolutely denied the claims.