BBC: As one of the leading Western analysts of Russian military developments, Roger McDermott, says, "while Russia's armed forces' leadership remain very interested in military theory, they test and rehearse new approaches to warfare in strategic exercises".
Thus, he adds, "exercises like Zapad offer glimpses into the real level of capability and demand careful and sober assessment for outsiders".
Russia claims this exercise falls below a treaty threshold of 13,000 soldiers that would require invitations to be issued to observer teams from other European nations. Western analysts place the numbers involved much higher.
But even without full-scale observer teams, Zapad is being monitored closely by Nato countries using satellites and aircraft with radars that can reach into western Russia to get a clear sense of how Russian and Belarussian forces perform.
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