Russian forces have reached the outskirts of Toretsk, an eastern Ukrainian frontline city, just days after capturing the strategic town of Vuhledar, Ukraine's military reported late Monday.

"The situation is unstable, fighting is taking place literally at every entrance (to the city)," Anastasiia Bobovnikova, spokesperson of the Operational Tactical Group "Luhansk" told Ukraine's national broadcaster.

"The Russians have entered the eastern outskirts of the city."

There was no immediate comment from the Russian Defense Ministry, which said earlier Monday that its forces inflicted damage to manpower and equipment near several settlements in the area, including near Toretsk.

Russian military bloggers, including a group of military analysts who ran the prominent Rybar Telegram channel, said Russian troops continue to advance towards the center of the town.

The advance of Moscow's forces – just like the capture of Vuhledar last week – has underlined Russia's vast superiority in men and materiel as Ukraine pleads for more weapons from the Western allies that have been supporting it.

Russia, which now controls just under a fifth of Ukrainian territory, has been advancing towards Toretsk since August, taking village by village with infantry aided by the increased use of the highly destructive guided bombs.

With Ukraine now losing more and more territory, President Volodymyr Zelenskyy has ordered his top brass to do "everything that can be done" to minimize Moscow's advance along the frontline.

For Ukraine, Toretsk has been a frontline city for 10 years now, as it is close to Ukraine's territories seized by Russian-backed separatists in 2014. It has since become an anchor of Kyiv's fortifications.

For Moscow, seizing the town, known until 2016 under the Soviet name of Dzerzhinsk, after Felix Dzerzhinsky, the founder of the Soviet secret police, would bring closer President Vladimir Putin's goal of taking the Donbas region.

The fall of the hilltop Toretsk, Ukrainian military analysts say, would let Moscow obstruct key logistical routes connecting the operational rear of Kyiv forces in the area with the combat zone, including the major Pokrovsk-Kostyantynivka road.

After failing to capture the capital Kyiv when launching Moscow's full-scale invasion in February 2022, Putin focused on taking eastern Ukraine's Donbass, the old industrial heartland that covers the Luhansk and Donetsk regions.

Donbas has since become the war's main theatre where some of the biggest battles in Europe for generations have taken place.