A week after Russia captured Vuhledar, a town that anchored Ukraine’s defenses in the country’s southeast, Moscow’s forces are continuing to advance in the area, pushing into or flanking several towns as they try to break through Ukrainian lines.

Russian troops have now entered Toretsk, a city about 50 miles north of Vuhledar, and are advancing toward its center, according to battlefield maps compiled by independent groups analyzing combat footage. A Ukrainian Army spokeswoman, Anastasia Bobovnikova, said late Monday that Russia had entered the city, noting that “fighting is taking place literally at every entrance” to it.

The Russian Army has also made small advances along the jagged, curving front line that stretches from Toretsk to Vuhledar in eastern Ukraine’s Donetsk region, closing in on several strategic towns and cities, the battlefield maps show.

The fierce fighting in the area reflects the Kremlin’s longstanding goal of capturing all of the Donetsk region, which it already partly controls. “This is clearly what the Russians are aiming at,” said Franz-Stefan Gady, a Vienna-based military analyst. “As a result, this is where the heaviest fighting is happening.”

The flurry of activity in eastern Ukraine contrasts with the situation in the Kursk region in western Russia, which Ukrainian forces partly invaded in August. Kyiv’s troops made swift gains early in the offensive, some of which were reversed by Russian counterattacks last month. The front line has recently stabilized, with each side making only marginal advances.