Gains come even as Kremlin’s war machine stumbles and Ukrainian strikes hit Russia’s oil sector and spark fuel shortages

Kostiantynivka is the southernmost of four key settlements forming a defensive line central to Ukraine's effort to hold the Donetsk region

Small groups of Russian soldiers attempt to infiltrate outskirts of Kostiantynivka in heavily industrialised Donetsk region, suggesting close-quarters assaults could follow.

Gains come even as Kremlin’s war machine stumbles and Ukrainian strikes hit Russia’s oil sector and spark fuel shortages