Ukraine’s President Volodymyr Zelenskyy has said troops had “liberated dozens of settlements” and reclaimed more than 1,000 square kilometres (385 square miles) of territory in the Kharkiv region in the east as well as in Kherson in the south over the past week.
Zelenskyy on Friday posted a video of Ukrainian soldiers announcing they had captured the eastern town of Balakliia, south of Kharkiv, Ukraine’s second-largest city. The Ukrainian military said it had advanced nearly 50km (31 miles) through that front after an assault that appeared to take the Russians by surprise.
The Ukrainian general staff said early on Friday that retreating Russian forces were trying to evacuate wounded personnel and damaged military equipment near Kharkiv.
“Thanks to skilful and coordinated actions, the Armed Forces of Ukraine, with the support of the local population, advanced almost 50km in three days,” he said.
The surprise Ukrainian breakthrough in the east came a week after Kyiv announced the start of a long-awaited counteroffensive hundreds of kilometres away at the other end of the front line, in Kherson province in the south.
The Ukrainian breakthrough near Kharkiv was the fastest advance reported by either side for months, and one of the biggest shifts in the war’s momentum since Russian forces abandoned a disastrous assault on the capital Kyiv in March.
Such rapid advances have largely been unheard of since Russia abandoned its assault on Kyiv in March, shifting the war mainly into a relentless grind along entrenched front lines.
Western military analysts said the advance puts the Ukrainians within striking distance of the main railway Moscow has relied on to sustain its force in eastern Ukraine, and could leave thousands of Russian troops at risk of being cut off.
The Kremlin declined to comment on the advance and referred questions to the Russian military.
Russian state television broadcast an interview on Friday acknowledging that Kyiv had achieved a “substantial victory” in Kharkiv and Russia’s defence ministry released a video of its troops being rushed to reinforce the area.
“The very fact of a breach of our defences is already a substantial victory for the Ukrainian armed forces,” Russian state TV showed the head of the Russian-installed occupation administration for Kharkiv province, Vitaly Ganchev, saying in an interview. Russian law bans all reporting of the conflict that diverges from official accounts.
Ukraine has not allowed independent journalists into the area to confirm the extent of its advances, but Ukrainian news websites have shown pictures of troops cheering from armoured vehicles as they roar past street signs bearing the names of previously Russian-held towns.
“We see success in Kherson now, we see some success in Kharkiv and so that is very, very encouraging,” US Secretary of Defense Lloyd Austin told a news conference with his Czech counterpart in Prague.
The Institute for the Study of War think-tank said the Ukrainians were within 15km (nine miles) of Kupiansk, a junction for the main railway lines that Moscow has relied on to supply its forces on the battlefields in the east.
Ukrainian officials say Russia moved thousands of troops south to respond to the Kherson advance, leaving other parts of the front line exposed and creating the opportunity for the lightning assault.
“We found a weak spot where the enemy wasn’t ready,” presidential adviser Oleksiy Arestovych said in a video posted on YouTube.
Arestovych acknowledged progress in the south had not yet been as swift as the sudden breakthrough in the east.
Moscow has long used its firepower advantage to make slow advances by bombarding towns and villages. But that tactic has depended on tonnes of ammunition a day reaching the front line by train from western Russia.
Tens of thousands of people have been killed, millions have been driven from their homes and Russian forces have destroyed entire cities since Moscow launched what it calls a “special military operation” in February to “disarm” Ukraine. Russia has denied intentionally targeting civilians.