Russian forces pounded frontline cities in eastern Ukraine with air strikes and artillery attacks, while U.S. officials stepped up efforts to locate the source of a leak of classified U.S. documents, including those on Ukrainian counter-offensive plans. The Russians pressed on with their offensive in the eastern Donetsk region where several cities and towns came under heavy bombardment, Ukraine's general staff said on Tuesday. Ukrainian forces repelled several attacks, it said, as the Russian military kept up its effort to take control of Bakhmut. A top Ukrainian commander accused Moscow of using "scorched earth" tactics.