The front currently ran roughly along the Vovcha River which bisects the town of Vovchansk, Syniehubov told national television on Monday.

Russian forces were failing to make further advances, he added.

"On the contrary, our soldiers are trying to retake this settlement house by house and street by street," he said.

He added that the Russian advance further to the west had also been halted.

The information from Syniehubov could not be independently verified.

Russian forces launched a fresh offensive on the Kharkiv region from across the border 10 days ago, to extend the front and overwhelm Ukrainian defences.

After initial successes and the seizure of several villages, the pace of the advance has slowed, but it has not been completely halted, according to independent observers.