Fighting has gripped the area around the shattered eastern Ukrainian town of Avdiivka, Ukraine's military says, with Moscow's forces intensifying air bombardments and trying to move forward with ground forces.
Officials said Russian forces had suffered heavy losses around the city. They also said Ukrainian forces had repelled Russian attacks in other areas of the 1,000-km front line.
Russia has focused on eastern Ukraine since failing to advance on Kyiv in the early days of the 20-month-old war and in mid-October launched a push to seize Avdiivka -- 20 km from the Russian-held city of Donetsk.
"Fighting is still going on. Over the last two days, the occupiers have increased the number of air strikes using guided bombs from Su-35 aircraft," Ukrainian military spokesman Oleksandr Shtupun told national television.
"The enemy is also bringing in more and more infantry. But when they tried to deploy armoured vehicles the day before yesterday two tanks and 14 other vehicles were burned out."
Ukrainian forces, he said, had repelled eight attacks in the past 24 hours on the city, known for its vast coking plant.
Vitaliy Barabash, head of Avdiivka's military administration said "not a single building" was intact in the city, with just over 1,500 of its pre-war population of 32,000 remaining and evacuations proceeding. The hospital was functioning under constant shelling and a single shop was open.
Russian accounts said Moscow's forces had repulsed five Ukrainian attempts to advance on villages outside Bakhmut, a town captured by Russian troops in May after months of fighting.
Ukrainian Commander-in-chief, General Valery Zaluzhnyi, said he had discussed the "hottest sectors" of the front line with Charles Brown, US Chairman of the Joint Chiefs of staff.
Zaluzhnyi this month said the war was entering a phase of attrition, prompting President Volodymyr Zelenskiy to dismiss any notion that the conflict was headed towards stalemate.
Earlier, two Russian state news agencies published alerts saying Moscow was moving troops to "more favourable positions" east of the Dnipro River in Ukraine, only to withdraw the information minutes later.
The highly unusual incident suggested disarray in Russia's military establishment and state media over how to report the battlefield situation in southern Ukraine.
Russia retreated a year ago from areas it had seized on the western bank of the Dnipro, including the regional capital Kherson. If Ukrainian forces succeeded in crossing the river and establishing a secure bridgehead on the east bank, it would represent a major advance.
Natalia Humeniuk, a spokesperson for Ukraine's southern military command, said Monday's incident was symptomatic of information warfare.
Ukraine has said little about its military operations on the east bank of the Dnipro. Last week, in a statement that Reuters could not independently verify, Russia's military said it had thwarted a Ukrainian attempt to create a bridgehead there.
The US-based Institute for the Study of War said last week that Ukraine appeared to have conducted assaults across the Dnipro in Kherson region in mid-October, and noted that Russian military bloggers were reporting continued Ukrainian ground operations on the east bank.
President Volodymyr Zelenskiy told Reuters in an interview last week that Ukraine's five-month-old counter-offensive was making some gradual progress in the south and east, including what he called "good steps near Kherson region".
