Updated at 3 p.m. ET
In one of the biggest shows of military might since the end of the Cold War, Russia and Belarus are conducting joint maneuvers on NATO's doorstep, where the exercises are prompting jitters in some former Soviet satellites.
Ukrainian President Petro Poroshenko has stepped up security on his country's border with Belarus, warning that the Zapad 2017 exercises could be a prelude to an invasion. Zapad means "west" in Russian