Ukraine pressed an offensive in the east of the country on Friday, seeking to cut off Russian forces as Kyiv achieved its biggest breakthrough in months of grinding combat. Over the past three days, Ukrainian forces have advanced almost 50 kilometers, or about 31 miles, in the northeastern Kharkiv region, the army general staff said Friday. Images of the Ukrainian flag being raised over local government buildings and residents greeting soldiers with tears of joy have boosted morale across the country after months on the defensive. One video showed Ukrainian soldiers in the city of Balakliya clambering on top of...