Russian forces are intensifying their drive to capture the eastern Ukrainian town of Avdiivka, trying to advance on all sides after weeks of fighting, the town's top official was quoted as saying on Monday.

Russian troops have been pressing land and air-based attacks on Avdiivka, since mid-October as the focal point of their slow-moving push through eastern Ukraine's Donbas region in the 21-month-old war.

The latest push, reported by Vitaliy Barabash, head of Avdiivka's military administration, followed reports last week that Ukrainian troops had made some headway in halting and pushing back the Russian advance.

"Things in the Avdiivka sector have become even tougher. The intensity of clashes has been increasing for some time," Barabash told the media outlet Espreso TV.

"The Russians have opened up two more sectors from which they have begun making assaults - in the direction of Donetsk ... and in the so-called industrial zone. The enemy is attempting to storm the city from all directions."

Officials say not a single building remains intact after months of battles in the town noted for a vast coking plant. Fewer than 1,500 residents remain of 32,000 before the war.

Much of the fighting has focused on the industrial zone and the coking plant.

Barabash earlier said that Ukrainian forces had in recent days pushed back Russian forces near Stepove, a village northwest of Avdiivka, pinning them down near a rail line.

Ukrainain and Western military analysts say Russia has incurred heavy losses, although the battle for the town is rarely mentioned in official Russian military dispatches.

Russian military bloggers also reported Ukrainian gains near Avdiivka last week. On Monday, Russian reports said Moscow's troops had secured control of the industrial zone and were attempting to storm the coking plant.

Reuters could not verify reports from either side.

Avdiivka was briefly captured in 2014 by Russian-financed separatists who seized large chunks of eastern Ukraine.

Fortifications were later built around the town - seen as a gateway to the Russian-held regional centre of Donetsk - and it has resisted attacks since Moscow began its full-fledged invasion in February 2022.

Ukraine launched a counteroffensive in June but has made only marginal gains in both the east and the south. President Volodymyr Zelenskiy has acknowledged the slow progress but denies any suggestion the war is at a "stalemate".

Ukrainian military spokesperson Oleksandr Shtupun told the news outlet liga.net that wintry weather and strong winds were affecting the use of drones by both sides.

Shtupun said Russian forces had suffered heavy losses near Avdiivka and nearby Maryinka, another largely destroyed town where control has been contested for months.

"Our defenders are holding their ground," Shtupun told liga.net. "We are fighting and will continue to fight despite the weather."