“Russia and Belarus have encountered unprecedented threats, the nature and, perhaps, concentration of which are, unfortunately, much larger and much more dangerous than before,” he told reporters.

Russia has launched a series of simultaneous rapid-fire military exercises and has deployed warships to the Black Sea, while Ukraine announced its own 10-day military drills starting Thursday, using unmanned aircraft and antitank missiles supplied by Kyiv’s Western partners.

After months of a massive Russian military buildup on Ukraine’s borders, military analysts are warning that the final pieces are largely in place for a major strike that could topple Kyiv’s pro-Western government and reassert Moscow’s control.