(Bloomberg) -- Ukrainian troops will pull back from Sievierodonetsk, according to a senior local official, as Russia concentrates its forces to capture a city that became a key target in the Kremlin’s war effort after its failed assault on Kyiv. 

Troops will withdraw from the city after constant shelling for months destroyed 90% of its buildings, Serhiy Haiday, the region’s governor, said in a television interview Friday. Russian forces are moving in on the neighboring city of Lysychansk, Ukraine’s last major holdout in the Luhansk region, he added. 

Kremlin spokesman Dmitry Peskov referred all questions about the evacuation of civilians from the area to the Defense Ministry. Ukrainian military spokesman Oleksandr Motuzyanyk declined to comment on troop positions at a briefing Friday, calling the information classified. 

Russia’s momentum in eastern Ukraine comes after Vladimir Putin shifted his nation’s war goals following initial missteps during the siege of Kyiv that led to steep losses and a retreat. 

Kremlin forces are now focused on capturing Donbas, an industrial area consisting of the Luhansk and Donetsk regions that has been partially controlled by two self-declared republics since 2014. Sievierodonetsk has served as the Luhansk region’s administrative center after the Russian-backed fighters took over its capital at the time.

The war has evolved into a grinding fight in which Russia is leveraging its superior firepower to pound Ukrainian positions before advancing. Several major cities, including Kharkiv in the northeast and the southern port of Mykolaiv, have also been targeted more frequently by Russian missiles and artillery in recent weeks. 

“They have very primitive tactics, they use as much artillery and bombing capacity as possible to minimize resistance,” Ukraine President Volodymyr Zelenskiy said Thursday in a video address to the Hebrew University of Jerusalem.

Kyiv has been pressing its NATO allies to provide it with more weapons as the Russian offensive continues to advance. The US said Thursday it will provide an additional $450 million in military aid, bringing the total security assistance provided since February to about $6.1 billion. 

“We are having a very hard time because the firepower advantage is on the side of the enemy,” Valeriy Zaluzhnyi, the Commander-in-Chief of Ukraine’s military, said on Facebook Friday, calling the situation “difficult, but under control.”

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