Neither Russia nor Ukraine has made any significant territorial gains for almost a year, and Kyiv's top army commander said last week the war had ground to a stalemate.

But fighting has remained intense, with both sides claiming to have inflicted heavy losses on the other.

Ukraine said 400 individual "combat clashes" took place over the last seven days, and that Russia was continuing its offensive on Avdiivka -- an industrial town in the eastern region of Donetsk that Russia has been trying to surround and capture for months.

"The enemy is conducting assault actions in several directions at once," Andriy Kovalyov, a spokesperson for the general staff of Ukraine's armed forces, said on Monday in an interview on state TV.

Kovalyov also reported Russian attacks near the village of Robotyne, which Ukraine regained control of earlier this year, in the southern Zaporizhzhia region.

"The enemy attempted to restore its lost position near Robotyne but had no success," Kovalyov said.

Russia's defence ministry said on Sunday it had repelled Ukrainian attacks near Robotyne.

In a briefing with top military commanders, Russian Defence Minister Sergei Shoigu said last week his forces were "continuing to conduct an active defence, inflicting effective damage on the enemy" and that Russian "units are moving forward, occupying more advantageous positions".

Ukraine's Kovalyov said on Monday that Kyiv was conducting its own "offensive operations" to the south of Bakhmut -- a city destroyed by months of artillery fire and urban warfare before Russia eventually captured it in May.

AFP could not verify either side's claims.

Both the Kremlin and Ukrainian President Volodymyr Zelensky have denied the conflict has reached a deadlock, although the sprawling frontline has barely moved in a year despite a months-long Ukrainian counter-offensive.