Ukrainian forces are advancing into the Kharkiv region, pushing back the Russian line, according to the U.K. Defense Ministry on social media.
The territory in the east of the country was captured early on in the invasion, but a Ukrainian counterattack launched earlier in the week is driving into Russian-held territory.
The British military writes that the attack has penetrated 50 kilometers into what had been the Russian front-lines. “Russian forces were likely taken by surprise. The sector was only lightly held and Ukrainian units have captured or surrounded several towns,” the ministry said.
According to Ukraine’s official defense ministry twitter account: “Armed Forces have liberated and took control of more than 30 localities in the Kharkiv region.”
Amid the unexpected success of the counterstrike, footage has emerged of Ukrainian citizens in formerly occupied areas greeting the advancing troops as liberators.
The Washington-based think tank Institute for the Study of War estimates that the offensive has resulted in the capture of 2,500 square kilometers as of September 9.
The counterattack marks the biggest involuntary reversal on the part of the Russian military in the conflict so far. According to the U.K. Defense Ministry it could lead to even bigger gains for the Ukrainian forces.
“A Russian force around Izium is likely increasingly isolated. Ukrainian units are now threatening the town of Kupiansk; its capture would be a significant blow to Russia because it sits on supply routes to the Donbas front line,” the ministry said.