Peskov’s comments came as Ukraine’s president, Volodymyr Zelenskiy, said civilians would need to be dug from bunkers under the steelworks which is littered with concrete debris.

Ukrainian officials believe that about 200 civilians remain trapped along with fighters in the network of underground bunkers at the sprawling Soviet-era complex.

Having failed to capture the capital, Kyiv, in the early weeks of an invasion that has killed thousands and flattened towns and villages, Russia has accelerated attacks in southern and eastern Ukraine.

Putin called off plans for an assault on the plant last month, telling his defence minister to seal it off instead.

Russia’s defence ministry added on Thursday that its artillery had struck multiple Ukrainian positions and strongholds overnight, claiming it had killed 600 fighters.

The defence ministry also said its missiles destroyed aviation equipment at the Kanatovo airfield in Ukraine’s central Kirovohrad region and a large ammunition depot in the southern city of Mykolaiv.

The Russian claims of Ukrainian fatalities in the hundreds were impossible to verify and reflect statements by both Ukrainian and Russian officials in recent days, both claiming heavy enemy losses.

Ukraine and Russia have both said that fighting had been heavy across the south and east over the past day.

While it is difficult to assess accurate casualty numbers, senior western officials who have briefed journalists recently suggested that Russian losses may have declined somewhat since the heavy casualties incurred during the failed campaign to take Kyiv.

There are also suggestions that Ukrainian losses may be mounting under intense Russian artillery bombardments that have marked Moscow’s conduct of the latest phase of the war.

With Ukraine’s western allies rushing to supply Kyiv with artillery systems and shells to counter Russia’s, the conflict in Ukraine appears to be turning into a grinding artillery duel between the two sides, with Russian advances limited to a small number of kilometres each day.

Despite claims of Ukrainian counteroffensives in the east, these appear to have been limited in scope, with an adviser to Zelenskiy having said that Ukraine was unlikely to launch a significant counteroffensive before mid-June, when it hopes to have received more weapons from its allies.

While senior western officials have spoken openly about their desire to leave Russia “weakened” by its invasion of Ukraine, the Kremlin on Thursday accused the west of preventing a “quick” end to Russia’s military campaign.

The wives of at least two Ukrainian soldiers inside Azovstal have been in Rome, pleading with the international community for an evacuation of the soldiers there, arguing they deserve the same rights as civilians.

Kateryna Prokopenko, the wife of the Ukrainian commander at the plant, said she gone without word from him for more than 36 hours before finally hearing from him on Wednesday.

Should the Azovstal fighters be taken captive, it’s not clear whether Russia would uphold its commitments under international law regarding prisoners of war, given its alleged previous violations of rules governing wartime conduct and a lack of evidence of its treatment of captured Ukrainian troops.