KYIV/KHARKIV, (Ukraine): Ukrainian forces endured heavy artillery barrages on Sunday as they held off Russian attempts to capture Sievierodonetsk, the largest city Kyiv still controls in the Luhansk region of the Donbas, Ukrainian officials said.

The shelling was so intense it was not possible to assess casualties and damage, Luhansk governor Serhiy Gaidai said. Dozens of buildings have been destroyed in the past few days.

“The situation has extremely escalated,” Gaidai said.

The Ukrainian government meanwhile urged the West to provide it with more longer-range weapons in order to turn the tide in the war, now in its fourth month.

The battle for Sievierodonetsk, which lies on the eastern bank of the Siverskyi Donets River, is in the spotlight as Russia ekes out slow but solid gains in the Donbas, comprising of the Luhansk and Donetsk regions.

Having failed to take the capital Kyiv in the early phase of the war, Russia is seeking to consolidate its grip on the Donbas, large parts of which are already controlled by Moscow-backed separatists.

It has concentrated huge firepower on a small area - a contrast to earlier phases of the conflict when its forces were often spread thinly - bludgeoning towns and cities with artillery and air strikes.

Governor Gaidai said on Sunday that Russian forces had dug in at the Myr hotel on Sievierodonetsk’s northern edge.

“They cannot advance further into the city and are taking casualties, but we are not able right now to push them out of the hotel,” he said on Telegram.

Analysts at the Institute for the Study of War in Washington said the Russians had still not managed to encircle the city and the Ukrainian defenders have inflicted “fearful casualties” on them.

The Ukrainians were taking serious losses themselves, civilians as well as combatants, they said in a briefing paper.

Russia’s focus on Sievierodonetsk had drawn resources from other battlefronts and as result they had made little progress elsewhere, the analysts said.

A Reuters journalist in the area said a ceramics factory was almost completely destroyed on the outskirts of the Donetsk town of Bakhmut, which straddles the last main road into Sievierodonetsk and is just 10 km (6 miles) from the frontline.

The journalist heard what appeared to be outgoing artillery fire and Russian aircraft dropping a bomb close to the town. The city itself was not badly damaged and while the town was relatively empty, some residents were walking with pets and children.