Ukrainian President Volodymyr Zelensky on Monday said his troops were facing complicated fighting along sections of the sprawling front line, with delays in Western military aid impacting his army.

Moscow’s forces are back on the offensive in eastern and southern Ukraine, and captured Avdiivka in the eastern Donetsk region, securing their first major gain since taking Bakhmut in May 2023.

“The situation is extremely difficult in several parts of the front line, where Russian troops have concentrated maximum reserves,” Zelensky said.

He was returning from a trip to brigades around the northeastern city of Kupiansk, in the frontline Kharkiv region.

Russian troops “are taking advantage of the delays in helping Ukraine,” Zelensky continued, adding his country faced artillery shortages and needed frontline air defence capabilities as well as longer-range weapons.

Earlier in the day, Ukrainian troops said they were facing “heavy fire” from advancing Russian forces in the southern Zaporizhzhia region.