STORY: Russia's defense ministry said on Saturday that it was pulling troops out of its main stronghold in northeastern Ukraine, a sudden collapse of one of the war's principal frontlines after Ukrainian forces encircled the area in a surprise advance.
Video posted on social media showed Ukrainian troops driving past a tank bearing the Russian pro-war “Z” symbol in the city of Kupiansk - shortly after capturing the single railway hub that supplies Russia's entire frontline across northeastern Ukraine.
That left thousands of Russian troops abruptly cut off from supplies across an entire stretch that has seen some of the most intense battles of the war.
A separate social media video showed Ukrainian military at the entrance of Izium after Moscow abandoned the city.
Russia's defense ministry said it ordered troops to leave the area in order to reinforce operations in neighboring Donetsk.
The swift fall of Izium is Moscow's worst defeat since its troops were forced back from the capital Kyiv in March.
It could prove to be a decisive turning point in the six-month war, with thousands of Russian soldiers apparently abandoning their ammunition stockpiles and equipment.
Ukrainian forces report recapturing dozens of towns and villages held by Russia for months, since bursting through the frontline just days ago.
Video just released by Ukraine's Ministry of Defense showed troops raising the country's blue and yellow flag in Balakliia, from where Russian forces recently fled.
But despite the counter-offensive in the region, the war rages on, Russian rocket fire hit Kharkiv Saturday evening bringing yet more death and destruction.