The force that’s moving toward Sumy is the same group they spent months assembling to push us out of Kursk Oblast—about 70,000 Russian troops,” said Dykyi, a former Aidar Battalion company commander.

Russian forces are advancing in the northern Ukrainian region of Sumy, bringing the regional capital within range of their drones and artillery, according to Ukrainian officials and analysts.

Senior Ukrainian officials visited Washington on Tuesday seeking U.S. support against Russia, as Kyiv showed its ability to fight on by setting off an explosive device under a bridge that has become a symbol of the Kremlin's claims on Ukrainian territory.