Russia Completes Joint Military Exercise with Belarus in the Baltic Sea

Russia and Belarus concluded their large-scale joint military exercise, Zapad-2025, in the Baltic Sea and surrounding regions on September 13, 2025. The drills, which began on September 12, involved coordinated maneuvers in both countries as well as in the Baltic and Barents seas, according to the Russian defense ministry. The exercise was designed to enhance the operational coordination and field training of the two countries' regional and coalition forces, with Russian officials emphasizing that the maneuvers were not directed against any specific nation.

Regional Tensions and Security Responses

The timing of Zapad-2025 has drawn significant attention, coming just days after Poland shot down suspected Russian drones over its airspace. In response to the exercise and perceived aggressive military posturing, Poland closed its border with Belarus at midnight on September 11, citing direct threats to national security. Polish officials stated that the closure would remain until they were confident that no provocations or threats to Polish citizens persisted. Neighboring NATO members, including Lithuania and Latvia, also increased their border security and launched parallel military exercises, reflecting heightened regional alertness.

Scale, Participation, and International Observers

Belarus reported that approximately 13,000 personnel participated in Zapad-2025, a significant reduction from previous iterations, though analysts suggest the true scale may be larger due to dispersed activities. The exercise included training related to nuclear weapons employment and the use of Russia's Oreshnik missile system, which is nuclear-capable and expected to be delivered to Belarus later in 2025. Belarus invited all 56 OSCE Vienna Document states, including NATO members, to observe the drills, though the transparency of actual participation numbers remains debated among Western analysts.

Broader Military Context and Diplomatic Fallout

The Zapad-2025 exercise occurred alongside other major military maneuvers in the region, such as Poland's "Iron Defender," Lithuania's "Thunder of Perkunas 2025," and Latvia's "Namejs 2025," each involving thousands of troops. The exercises have further strained relations between Belarus and its Western neighbors, with both sides engaging in diplomatic and security escalations. Notably, on the eve of the drills, Belarus released and deported 52 political prisoners to Lithuania after negotiations with the U.S., a move interpreted by some analysts as an attempt by President Lukashenko to balance relations amid mounting pressure from Russia and the West.

While Russian and Belarusian officials maintain that Zapad-2025 was purely defensive, Western governments and analysts remain wary, viewing the exercise as both a demonstration of military capability and a potential cover for more aggressive actions near NATO's eastern flank.