The Ukrainian army has retreated from an area on the outskirts of Chasiv Yar, a strategically important town in the eastern Donetsk region which was reduced to rubble under a months-long Russian assault.
Chasiv Yar lies a short distance west of Bakhmut, which was captured by Russia last year after a bitter 10-month battle.
For months, Russian forces have focused on capturing Chasiv Yar, a town which occupies a strategic, elevated location.
Its fall would put nearby cities in jeopardy, compromise critical Ukrainian supply routes and bring Russia closer to its stated aim of seizing the entire Donetsk region.
The Ukrainian army retreated from a north-eastern area in the town of Nazar Voloshyn, the spokesman for the Khortytsia ground forces formation, told The Associated Press.
Ukraine’s defensive positions in the town were “destroyed”, he said, adding that there was a threat of serious casualties if troops remained in the area and that Russia did not leave “a single intact building”.
Months of relentless Russian artillery strikes have devastated Chasiv Yar, with homes and municipal offices charred, and a town that once had a population of 12,000 has been left deserted.
The intensity of Russian strikes on Ukraine’s defensive line in the area of Chasiv Yar has increased over the last month, Mr Voloshyn said.
In the past week alone, he said Russia has carried out nearly 1,300 strikes, fired nearly 130 glide bombs and made 44 ground assaults.
Other Russian attacks in recent weeks have focused on capturing nearby settlements that would allow them to advance to Kramatorsk and Sloviansk, the biggest cities in the Ukrainian-controlled part of the Donetsk region.
Ukrainian commanders in the area say their resources remain stretched, largely due to a months-long gap in military assistance from the US which threw Ukraine’s military onto the defensive.
In June, members of the artillery brigade in Chasiv Yar reported that supplies of American ammunition had started to arrive.
Elsewhere in Ukraine, the governor of the northern Chernihiv region, Viacheslav Chaus, said Russia launched 22 drones over Ukraine last night.
One hit an infrastructure facility in the northern Chernihiv region, leaving nearly 6,000 customers without electricity, he said.
The rest of the drones were shot down, according to the air force’s morning update.
Russia is continually targeting Ukraine’s badly-damaged energy infrastructure, resulting in hours of rolling blackouts across the country.
Ukrainian officials have warned that the situation may worsen as winter approaches.