Local officials said that Russian forces have blown up a bridge connecting the disputed Ukrainian city of Sievierodonetsk to another town across the river, cutting off a possible evacuation route for civilians.
Sievierodonetsk has become the epicenter of the struggle for control of Ukraine’s eastern Donbas region.
Parts of the city have been pulverized in some of the bloodiest fightings since the Kremlin unleashed its invasion on February 24.
On Sunday, Ukrainian and Russian troops were still fighting street by street there, Luhansk province governor Serhiy Gaidai said.
Russian forces have taken most of the city, but Ukrainian forces still control an industrial area and a chemical plant, sheltering hundreds of civilians.
But the Russians had destroyed a bridge over the Siverskyi Donets River connecting Sievierodonetsk to its sister city Lysychansk, Gaidai said.
That leaves only one of the three bridges standing and reduces the number of routes that could be used to evacuate civilians or for Ukrainian troops to retreat to positions on the western side of the river.
In Lysychansk, Russian shelling killed a woman and destroyed four houses and a shopping center, Gaidai said.
The head of the Sievierodonetsk government said just over a third of the city remained under the control of Ukrainian troops and about two-thirds in Russian hands.
“Our (troops) are holding a strong hold on the defensive line,” Oleksandr Stryuk told national television.
After being forced to scale back its initial campaign goals in Ukraine, Moscow has turned its attention to expanding control in the Donbas, where pro-Russian separatists have controlled much of the territory since 2014.
Sievierodonetsk is the last city in the Luhansk province of Donbas still held by Ukraine, and its loss would be a major strategic blow. A victory for the Russians would bring them a big step closer to one of Russian President Vladimir Putin’s goals in what he calls a “special military operation.”
Elsewhere, Russia’s Interfax agency reported that Russian cruise missiles destroyed a large depot of US and European weapons in the Ternopil region of western Ukraine.
The governor of Ternopil said rockets fired from the Black Sea at the town of Chortkiv partially destroyed a military facility and injured 22 people. A local official said no weapons were stored.
Reuters could not independently confirm the various accounts.
Moscow has repeatedly criticized the United States and other countries for supplying Ukraine with weapons.
Earlier this month, Putin said Russia would hit new targets if the West supplied Ukraine with longer-range missiles for use in high-precision mobile missile systems.
Ukrainian leaders in recent days have again urged western countries to speed up deliveries of heavy weapons as Russian artillery storms the east of the country.
South and southwest of Sievierodonetsk, Russian troops fired mortars and artillery around several settlements, according to the General Staff of Ukraine.
But it said Ukrainian troops had repulsed Russian attempts to advance into some communities.
Reuters could not independently verify the battlefield records.
Ukrainian forces have proven to be more resilient than expected. Still, the US-based Institute for the Study of War said that they will need consistent Western support if they use the last of their stockpiles of Soviet-era weapons and ammunition.
Putin says Russia’s actions are aimed at disarming and “denazify” Ukraine. Kyiv and its allies call it an unprovoked war of aggression to conquer territory.