Military spokesperson Oleksandr Stupun told Ukrainian TV that “fierce battles continue” in Avdiivka.
He added: “The enemy launched massive assault actions with the support of armoured vehicles in Avdiivka and Mariinka directions.”
This comes as Russia launches another attack on Ukraine with eight long-range ballistic missiles in Ukraine’s capital, Kyiv.
Ukrainian police have reported that four people were injured by shards of glass following the 4am strike.
As the war becomes increasingly difficult for Ukraine, President Volodymyr Zelensky is preparing to make one last plea for war funds from the US.
He will meet with Republican House speaker Mike Johnson and Senate leader Mitch McConnell in Washington as he tries to convince their party to support the $61billion (£48billion) military aid package proposed by President Joe Biden.
Republicans are holding up the package as they seek assurances from Mr Biden that he will deal with immigration from Mexico.
On Monday, Mr Zelensky told an address at Washington’s National Defense University: “When the free world hesitates, that’s when dictatorships celebrate.”
The Ukrainian president added: “He’s (Vladimir Putin) fighting Ukraine, but really, he’s up against all of free, united Europe. He’s wrecking everyday life in Ukrainian cities, but his real target is the freedom people enjoy from Warsaw to Chicago to Yokohama.
“Putin’s got buddies in this – each one a threat to any free nation, to regional or global order, to human rights and democracy, be it Hamas, Iran, North Korea, or others. No accidents here, they’re all linked by their hate for freedom.
“America and all free nations need to be confident in themselves, in their strength, in their leadership, so that dictatorships doubt themselves and their power to undermine freedom. When the free world hesitates, that’s when dictatorships celebrate, and their most dangerous ambitions ripen.”
