A military convoy arrives to a training ground at an undisclosed location in Belarus on Sept. 11, 2017. NATO and neighboring countries have expressed concern over the war games. (Vayar Military Agency photo via AP)
A Russian military helicopter flies over a training ground at an undisclosed location in Belarus on Sept. 12, 2017. Military officials in Belarus have sought to calm Western fears about Zapad. (Vayar Military Agency photo via AP)
Russian military pilots, right, report upon arrival at an air base in Belarus prior to the start of Zapad 2017. (Vayar Military Agency photo via AP)
A soldier with the Belarus military aims his anti-aircraft gun at a training ground at an undisclosed location in Belarus on Sept. 13, 2017. (Vayar Military Agency photo via AP)
Russian military pilots are presented with bread and salt as they arrive at an air base at an undisclosed location in Belarus on Sept. 12, 2017. Russia and Belarus are holding a massive war game, Zapad 2017, which states Sept. 14, 2017, near the borders of Poland, Estonia, Latvia and Lithuania. (Vayar Military Agency photo via AP)
Russian and Belarusian war game sites and Russian missile defense system ranges from Kaliningrad.
A multiple-launch rocket system vehicle is being prepared at a training ground in Belarus prior to Zapad. (Vayar Military Agency photo via AP)
The official representative of the Belarusian Ministry of Defence, Col. Vladimir Makarov, addresses the media during a briefing in Minsk, Belarus, on Sept. 14, 2017. Zapad involves thousands of troops, tanks and aircraft. (Sergei Grits/AP)
Belarusian army vehicles drive preparing for the Zapad war games. (Vayar Military Agency photo via AP)
Belarus' Col.Alexander Prokopenko, left, reads his order to start the drills at a training ground at an undisclosed location in Belarus on Sept. 14, 2017. (Vayar Military Agency photo via AP)