PAVEL POLITYUK RUSSIAN forces pounded frontline cities in eastern Ukraine with air strikes and artillery attacks, while U.S. officials attempted 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. "The enemy switched to so-called scorched…