Russian air-assault units have gained control of “advantageous positions” in part of the fiercely contested Donbas city of Bakhmut, according to Russia’s state media.

Moscow’s assault forces have created a “good bridgehead,” or a strong position in enemy territory to advance through the city, which Ukrainian forces are still defending, according to a Kremlin-backed official in the Luhansk region.

The positions are in the territory around Bakhmut’s non-ferrous-metals processing plant, former commander Andrey Marochko said on Sunday, according to Russian state media outlet Tass. Russian troops can therefore “control the movement” of Ukrainian fighters, he added.

The Donetsk city of Bakhmut has been the site of months of fierce battles between Russian and paramilitary forces against Ukrainian troops. Ukraine vowed to defend the “fortress” city, but Russian soldiers have slowly gained territory there in recent weeks. Analysts have begun to suggest that the battle is likely to end “imminently” in Bakhmut.

On Friday, Russian media quoted a “military correspondent” who said on Telegram that Wagner forces had entered the AZOM metal-processing plant from the north of the city. The units had begun to “move deep into the territory of the industrial enterprise,” the account attributed to an Alexander Simonov said. This account has also been referenced by the Wagner Group’s main Telegram channel.

However, the Washington-based Institute for the Study of War (ISW) said on Saturday that Wagner Group fighters are “likely becoming increasingly pinned in urban areas, such as the AZOM industrial complex.”

Because of this, Wagner mercenary units will find it “difficult to make significant advances,” the think tank argued. As of Saturday, Russian forces had not advanced further through Bakhmut, with heavy fighting continuing, the ISW said.

On Saturday, Wagner Group chief Yevgeny Prigozhin said he was around 0.75 miles from the center of Bakhmut, which is on the west side of the Bakhmutka river that flows through the city.

Also on Saturday, the British defense ministry said the Bakhmutka River had become the new front line in the center of the settlement, following Wagner gains in the east. Around the river is a “killing zone,” the ministry said, “likely making it highly challenging for Wagner forces attempting to continue their frontal assault westwards.”

The General Staff of Ukraine’s Armed Forces said on Sunday that Russian troops continued to “storm” the Donetsk settlement, but that Ukraine was still defending the city. On Sunday, Ukraine’s foreign minister, Dmytro Kuleba, stated that Kyiv’s forces remained in the city to prevent nearby settlements from suffering “the same fate.”

In a statement posted to Telegram on Friday, Prigozhin said it was a “known fact” that Ukraine was “preparing a counteroffensive” in Bakhmut.

“Of course, we are doing everything possible to prevent this from happening,” he added.

Ukrainian military spokesperson, Serhiy Cherevaty, said on Saturday that 221 troops fighting for Moscow had been killed, and another 300 wounded, in fighting for Bakhmut in the previous 24 hours. On Sunday, Russia’s defense ministry said more than 220 Ukrainian soldiers were killed in a single day across the Donetsk front line, but did not specify how many of these reported casualties were in Bakhmut.