Moscow's troops are pushing en masse toward the frontline town of Avdiivka, according to the local mayor, intensifying their monthslong effort to seize the industrial center.

Russia has invested heavily in capturing the town, which has been a flashpoint since it briefly fell to Kremlin-backed separatists in 2014.

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

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

Seizing Avdiivka would represent a much-needed victory for Russia in the run-up to the second anniversary of its full-scale invasion of Ukraine and the March presidential election.

Fewer than 950 people from an estimated pre-war population of some 33,000 remain in Avdiivka, a town dominated by a huge coking plant. 

The town sits in Ukraine's eastern Donetsk region, which the Kremlin claims as part of Russia, along with four other Ukrainian regions that Moscow claims it has annexed. 

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

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

Ukraine's armed forces reported Thursday that its troops had fended off 40 enemy assaults around Avdiivka over the previous 24 hours.

rc/kb (Reuters, AP, AFP, dpa)