Russian forces has reportedly launched massive storming of the eastern Ukrainian town of Avdiivka, in a culmination of a monthslong effort to capture the industrial hub.

"Unfortunately, the enemy is pressing from all directions. There is not a single part of our city that is more or less calm," The town's Ukrainian mayor Vitaly Barabash told state media Thursday.

"They are storming with very large forces," he added.

Moscow had launched a costly bid in October to seize the town, which has been caught up in fighting since 2014, when it briefly fell to Moscow-backed separatists.

The capture of Avdiivka would provide a much needed victory for Russia to bring home, in the run-up to the second anniversary of its fully-fledged invasion of Ukraine and its March presidential election.

Avdiivka is located in Ukraine's eastern Donetsk region, which the Kremlin claims is part of Russia, along with four other Ukrainian territories that Moscow says it has annexed.

Barabash characterized the fighting as "very hot" and "very difficult."

"The situation in some directions is simply unreal," he said.

Fewer than 950 people remain in the frontline town, of an estimated pre-war population of around 33,000 people, he said.