Russian forces are staging their heaviest assaults near the strategic eastern city of Pokrovsk, Kyiv's military said Monday, threatening a key supply route for Ukrainian troops struggling to fend off Moscow's 29-month-old invasion.

Fighting on the Pokrovsk front was the fiercest anywhere in the war-scarred east, the General Staff said in a regular battlefield update, adding Ukraine had fought off 52 Russian assaults there in the past 24 hours.

Pokrovsk, a transport hub with a pre-war population of 61,000, lies on a main road that serves as an important supply route to other embattled Ukrainian-held outposts, such as the towns of Chasiv Yar and Kostiantynivka.

"The greatest concentration of enemy attacks was around Zhelanne and Novooleksandrivka," it said, citing two villages that lie to the east of Pokrovsk.

Russia's defense ministry said Sunday that its forces had taken the villages of Prohres and Yevhenivka in Ukraine's eastern Donetsk region. Both settlements sit east of Pokrovsk. Kyiv did not comment on the claim.

Russia launched its full-scale invasion in Feb. 2022 and still occupies nearly a fifth of Ukraine. Ukrainian forces repelled the Russians from the outskirts of Kyiv early in the war and recaptured territory in the east and south later in 2022. But since a failed counteroffensive in 2023 Kyiv's troops have mainly been on the defensive this year.