Ukrainian troops are facing “heavy fire” from advancing Russian forces in the southern Zaporizhzhia region after Moscow last week made its most significant territorial gain in nine months, Ukrainian military officials said Monday. Russian forces are back on the offensive across eastern and southern Ukraine and have forced Kyiv into a hasty withdrawal from the town of Avdiivka in the eastern Donetsk region, securing their first major gain since the capture of Bakhmut in May 2023. Senior Ukrainian commander Oleksandr Tarnavsky said Monday that Russia was now launching multiple attacks near the v…