KYIV/HRAKOVE, Ukraine – Moscow abandoned its main bastion in northeastern Ukraine on Saturday, in a sudden collapse of one of the war’s principal front lines after Ukrainian forces made a rapid advance.

The swift fall of Izyum in Kharkiv province was Moscow’s worst defeat since its troops were forced back from the capital Kyiv in March. This could prove a decisive turning point in the six-month-old war, with thousands of Russian soldiers abandoning ammunition stockpiles and equipment as they fled.

Russian forces used Izyum as the logistics base for one of their main campaigns – a months-long assault from the north on the adjacent Donbas region comprised of Donetsk and Luhansk.

The state-run Tass news agency quoted Russia’s defence ministry as saying it had ordered troops to leave the vicinity and reinforce operations elsewhere in neighbouring Donetsk.

The head of Russia’s administration in Kharkiv told residents to evacuate the province and flee to Russia to “save lives,” Tass reported. Witnesses described traffic jams of cars with people leaving Russian-held territory.

The Russian withdrawal was heralded by Ukrainian leaders.

“The Russian army these days is demonstrating its best ability – to show its back,” President Volodymyr Zelensky said in a video address on Saturday evening.

Ukraine’s armed forces have liberated around 2,000 square kilometres of territory since a counter-offensive against Russia started earlier this month, he said.

Ukrainian officials stopped short of confirming they had recaptured Izyum, but Andriy Yermak, Zelensky’s chief of staff, posted a photo of troops on its outskirts and tweeted an emoji of grapes. The city’s name means “raisin.”

“The Russian army is claiming the title of fastest army in the world... keep running!” Yermak wrote on Twitter later.

The Russian withdrawal announcement came hours after Ukrainian troops captured the city of Kupyansk farther north, the sole railway hub supplying Russia’s entire front line across northeastern Ukraine. Ukrainian officials posted photos early on Saturday of their troops raising the country’s blue-and-yellow flag in front of Kupyansk’s city hall.

That left thousands of Russian troops abruptly cut off from supplies along a front that has seen some of the most intense battles of the war.

There were signs of trouble for Russia elsewhere along its remaining positions at the eastern front, with pro-Russian officials acknowledging difficulties at other locations.

Ukrainian armed forces are continuing to advance in different areas along the front, Zelensky said.

Mechanised assault

Days ago, Kyiv’s forces burst through the front line and have since recaptured dozens of towns and villages in a swift mechanised assault, surging forward dozens of kilometres a day.

“To achieve the stated goals of the Special Military Operation for the liberation of Donbas, it was decided to regroup the Russian troops located in the districts of Balakliya and Izyum for the purpose of increasing efforts in the Donetsk direction,” Tass quoted Russia’s defence ministry as saying.

Russian forces had already abandoned Balakliya days ago.

Ukraine’s deputy defence minister, Hanna Malyar, sounded a cautionary note, urging people not to report prematurely that towns have been “taken” just because Ukrainian troops have entered, as in Balakliya.

“A few days ago it was reported that troops had entered the town. Today, we have finally established control in the city, carried out all the necessary activities, and raised the flag,” she said.

In Hrakove, one of dozens of villages recaptured in the Ukrainian advance, Reuters saw burnt-out vehicles bearing the “Z” symbol of Russia’s invasion. Boxes of ammunition were scattered along with rubbish at positions the Russians had abandoned in evident haste.

“Hello everyone, we are from Russia,” was spray-painted on a wall. Three bodies lay in white body bags in a yard.

The regional chief of police, Volodymyr Tymoshenko, said Ukrainian police moved in the previous day, and checked the identities of local residents who had lived under Russian occupation since the invasion’s second day.

“The first function is to provide help that they need. The next job is to document the crimes committed by Russian invaders on the territories which they temporarily occupied,” he said.

‘Russia is retreating’

A witness in Valuyki, a town in Russia’s Belgorod region near the border with Ukraine, told Reuters she saw families from Kupyansk eating and sleeping in their cars along roads.

“I was at the market today and saw a lot of people from Kupyansk. They say half of the city was taken by the Ukrainian army and Russia is retreating... the fighting is getting closer,” the witness said.

Belgorod governor Vyacheslav Gladkov said officials were giving food and medical aid to people queuing at a crossing into Russia. Senator Andrey Turchak, from the pro-Kremlin United Russia party, reported more than 400 vehicles at the frontier.

Russian rocket fire hit Kharkiv city on Saturday evening, killing at least one person and damaging several homes, part of a surge in shelling since Kyiv’s counter-offensive, Ukrainian officials said.

Reuters could not confirm the battlefield accounts independently.

Russia’s abrupt abandonment of the front line south of Kharkiv city brought a sudden end to a period when the war was fought as a relentless grind on a static front, favouring Moscow’s advantage in raw firepower. REUTERS