Russian forces pressed attacks on frontline cities in eastern Ukraine on Monday (local time), while Ukrainian officials played down a report that Kyiv is amending some plans for a counter-offensive due to a leak of classified US 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 city on the edge of a chunk of Russian-controlled territory in Donetsk has for months been the biggest battleground of the war, now in its second year.
The head of the Moscow-controlled part of Donetsk, Denis Pushilin, said Russian forces now held 75 percent 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."
As the battles ground on, US media outlet CNN reported that Ukraine had been forced to amend some military plans ahead of its long-anticipated counter-offensive because of the leak of US documents.
US officials are trying to trace the source of the leak of dozens of secret documents. They detail an array of topics, including information on the Ukraine conflict, in which the United States 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.
The secretary of the National Security and Defense Council, Oleksiy Danilov, told Reuters: "The opinion of people who have nothing to do with this do not interest us... The circle of people who possess information is extremely restricted."
Some national security experts and US officials say they suspect the leaker could be American, but they do not rule out pro-Russian actors.
Kremlin spokesman Dmitry Peskov declined to comment on the leak, but added: "There is in fact a tendency to always blame everything on Russia. It is, in general, a disease."
HOT ON THE EASTERN FRONT
A Ukrainian counter-offensive has long been expected after months of attritional warfare in the east.
A Russian winter offensive failed to make much progress and its troops have been bogged down in a series of battles where any advances are incremental and come at a huge cost.
The Ukrainian defenders have also taken heavy casualties.
Syrskyi said Moscow was sending in special forces and airborne units to help their attack on Bakhmut as members of Russia's private mercenary Wagner group were exhausted.
Wagner mercenaries have spearheaded the assault on Bakhmut which has left it largely in ruins.
Reuters could not verify the battlefield accounts.
Ukraine's general staff said Russian forces had made unsuccessful advances on areas west of Bakhmut and at least 10 towns and villages had come under Russian shelling.
Donetsk is one of four provinces in eastern and southern Ukraine that Russia declared annexed last year and is seeking to fully occupy in what appears to be a shift in its war aims after failing to overrun the country after its February 2022 invasion.
Control of Bakhmut could allow Russia to directly target Ukrainian defensive lines in Chasiv Yar in the east and open the way for its forces to advance on two bigger cities in the Donetsk region - Kramatorsk and Sloviansk.
While Ukraine has said it wants to inflict as many casualties as possible on the Russian forces as its prepares its own counteroffensive, President Volodymyr Zelenskiy last week acknowledged that if troops risked being encircled they could be pulled back.
In other action, Russia's defence ministry said its forces destroyed a depot with 70,000 tonnes of fuel near Zaporizhzhia.
They destroyed Ukrainian army warehouses storing missiles, ammunition and artillery in the regions of Zaporizhzhia and Donetsk, the ministry said.
Ukraine also reported widespread Russian shelling in northern regions. Officials in the south said Russian aircraft had used guided bombs against towns in the Kherson region.
In a rare coordination between the warring parties, Russia and Ukraine carried out another prisoner swap, with 106 Russian captives freed in exchange for 100 Ukrainians.
Reuters