Russian troops have surrounded much of the eastern city of Bakhmut. But Ukrainian President Volodymyr Zelenskyy has renewed his pledge to defend it. He says the fall of Bakhmut could open the way for the Russians into other areas of the Donetsk region, including the strategic city of Kramatorsk.

Kramatorsk is about 50 kilometers from the frontlines. It's an important base of operations for the Ukrainian military. Russian forces targeted the city on Tuesday with a missile strike. The attack destroyed apartment blocks.

Russian President Vladimir Putin calls the fight in the east a fight for "the existence" of the Russian state. He told workers at an aircraft factory in Ulan-Ude that they have helped to push back against Ukrainians and their Western allies.

Russia's defense minister is making sure his forces are well-equipped to "fulfill their obligations." Sergei Shoigu ordered arms suppliers in the Moscow region to double production of high-precision missiles and to come up with new weapons.

US officials have accused Russian forces of a "lack of competence" with the weapons they have now. They say a Russian fighter jet collided on Tuesday with an American surveillance drone, forcing them to crash it into the Black Sea.

Russia's defense officials have denied the claim, saying the drone crashed after making what they called a "sharp maneuver."