Ukrainian officials said that Ukrainian Ground Forces shot down a Russian fighter jet near Bakhmut and made gains in northern parts of the city. Meanwhile, Yevgeny Prigozhin, the founder of the mercenary Wagner Group, which has spearheaded the Russian assault on the city, said in a social media post Wednesday that Russian forces have taken control of the settlement of Zaliznyanskoye and are expanding the encirclement of Bakhmut.

The claims couldn't be verified.

The battle for Bakhmut intensified after Russian forces captured the nearby town of Soledar in January. Russian forces must go through Bakhmut to push deeper into parts of the Donetsk province they don't yet control, though Western officials say that the capture of the city would have limited impact on the course of the war. An assessment by the U.K. Defense Ministry over the weekend said that paramilitary units from the Wagner Group had seized eastern parts of Bakhmut, with a river flowing through the city marking the front line of the fighting.

Russian troops have enveloped the city from three sides, leaving only a narrow corridor leading west. The only highway west has been targeted by Russian artillery fire, forcing Ukrainian defenders to rely increasingly on country roads, which are hard to use before the muddy ground dries.