Ukraine said on Tuesday its forces had recaptured villages from Russian troops, pressing a major counter-offensive in the northeast of the country that could signal a shift in the war’s momentum and jeopardise Russia’s main advance.

Tetiana Apatchenko, press officer for the 92nd Separate Mechanised Brigade, the main Ukrainian force near Kharkiv, confirmed that Ukrainian troops had recaptured the settlements of Cherkaski Tyshky, Ruski Tyshki, Borshchova and Slobozhanske, in a pocket north of Kharkiv in recent days.

Yuriy Saks, an adviser to defence minister Oleksiy Reznikov, said the successes were pushing Russian artillery out of range of parts of Kharkiv, Ukraine’s second largest city, which has been under bombardment since the war's earliest days.

“The military operations of the Ukrainian armed forces around Kharkiv, especially north and northeast of Kharkiv, are sort of a success story,” Saks told Reuters.

“The Ukrainian army was able to push these war criminals to a line beyond the reach of their artillery.”

The counterattack could signal a new phase in the war, with Ukraine now going on the offensive after weeks in which Russia mounted a massive assault that Ukrainian troops mostly held off.

By pushing back Russian forces who had occupied the outskirts of Kharkiv since the early days of the war, the Ukrainians are within striking distance of the rear supply lines sustaining the main Russian attack force.