Most of the eastern city of Severodonetsk is now controlled by the Russians, Serhiy Hayday, head of the Luhansk regional military administration, announced on Wednesday.
Earlier in the day, Ukrainian forces reported fierce battles taking place at several locations across the eastern city in Ukraine's Luhansk region.
"The Russians are destroying everything," Hayday said in a televised announcement, "They are firing tanks and artillery at residential buildings."
In an interview with news outlet RBC-Ukraine on Wednesday, Hayday said that earlier this week, Ukrainian special forces had managed to take control of almost half of the city.
But he said that when the Russian troops saw the Ukrainian advance, "they simply began to level it to the ground with air strikes and artillery."
Hayday explained that Ukrainian forces had no choice but to make a temporary tactical retreat from the central parts of the city due to the intense Russian bombardment.
The official said that despite the pullback, Ukraine has retained control of Serverodonetsk's industrial zone, a key area on the outskirts of the city.