Russia launched military maneuvers in its European exclave, Kaliningrad, on June 10, one day after NATO began its own war games near the Russian border.
The Russian Defense Ministry said military drills involving the Baltic Sea fleet, the Russian Air Force, and paratroopers are under way in Kaliningrad, Russia's westernmost region sandwiched between EU and NATO members Lithuania and Poland.
Meanwhile, NATO has launched one of its largest-ever military maneuvers in the former Soviet Baltic countries of Latvia, Lithuania, and Estonia.
The exercises come as tensions between NATO and Russia have spiked over its annexation of Ukraine's Crimea peninsula in March.
Around 4,700 troops and 800 military vehicles from 10 countries are participating in the exercises, which started in Latvia on June 9, moved to Lithuania on June 10, and conclude in Estonia later in the week.
Russia has objected to the drills, describing them as an "act of aggression."
Based on reporting by AFP and ITAR-TASS