KYIV--Russian forces pressed attacks on frontline cities in eastern Ukraine on Monday, while Ukrainian officials played down a report that Kyiv is amending some plans for a counter-offensive due to a leak of classified U.S. documents. The Russians were pounding Ukrainian positions around besieged Bakhmut in the eastern Donetsk region and other cities and towns with air strikes and artillery barrages, Kyiv said. "The enemy switched to so-called scorched earth tactics from Syria. It is destroying buildings and positions with air strikes and artillery fire," Colonel General Oleksandr Syrskyi, commander of Ukraine's ground forces, said of Bakhmut. The small and now largely ruined city on the edge of a chunk of Russian-controlled territory in Donetsk has for months been the biggest battleground of the war. The head of the Moscow-controlled part of Donetsk, Denis Pushilin, said Russian forces now held 75% of the city. Moscow's military was also targeting the city of Avdiivka. "The Russians have turned Avdiivka into a total ruin," said Pavlo Kyrylenko, Donetsk's regional governor, describing an air strike on Monday that destroyed a multi-storey building. "In total, around 1,800 people remain in Avdiivka, all of whom risk their lives every day." In Chasiv Yar, the first major town to Bakhmut's west, few buildings are left intact and locals lining up to collect food and other aid do not even flinch at the sound of artillery. "It used to be scarier but now we have got used to it," said 50-year-old humanitarian volunteer Maksym. "You don't even pay attention," he added, his words nearly drowned out by the sound of explosions. As the battles ground on, U.S. media outlet CNN reported that Ukraine was forced to amend some military plans ahead of its long-anticipated counter-offensive because of the leak of dozens of secret documents. U.S. officials are trying to trace the source of the leak, reviewing how they share secrets internally and dealing with the diplomatic fallout. The documents detail topics including information on the Ukraine conflict, in which Washington has supplied Kyiv with huge amounts of weapons and led international condemnation of Moscow's invasion. Asked about the report, Ukrainian presidential aide Mykhailo Podolyak said Kyiv's strategic plans remained unchanged but that specific tactics were always subject to change.