Sinihubov told national television on Monday that the front currently runs along the Vovcha River, which divides the city of Vovchansk in two.
Russian forces are failing to advance, he said.
"On the contrary, our troops are trying to capture this settlement house by house and street by street," he said.
He said that Russia's advance towards the west has also been stopped.
Sinihubov's information could not be independently verified.
Russian forces launched a new offensive across the border in the Kharkiv area 10 days earlier to advance the front and overwhelm Ukrainian defences.
According to independent observers, after initial successes and the capture of several villages, progress has slowed, but not stopped completely.
khz
Russian forces are failing to advance, he said.
"On the contrary, our troops are trying to capture this settlement house by house and street by street," he said.
He said that Russia's advance towards the west has also been stopped.
Sinihubov's information could not be independently verified.
Russian forces launched a new offensive across the border in the Kharkiv area 10 days earlier to advance the front and overwhelm Ukrainian defences.
According to independent observers, after initial successes and the capture of several villages, progress has slowed, but not stopped completely.
khz