“The great Ukrainian flag has been returned to Chkalovske. And it will be like that everywhere. We will cast out the occupiers from every Ukrainian town and village,” he said.

Ukraine’s military chief, General Valerii Zaluzhnyy, said on Sunday that Ukraine had liberated about 3,000 square kilometres (about 1,160 square miles) since the beginning of September. He noted that Ukrainian troops were now just 50km away from the border with Russia.

The Russians’ pullback marked the biggest battlefield success for Ukrainian forces since they thwarted a Russian attempt to seize the capital, Kyiv, at the start of the nearly seven-month war. Ukraine’s attack in the Kharkiv region came as a surprise for Moscow, which had relocated many of its troops from the area to the south in expectation of the main Ukrainian counteroffensive there.

Crates of dumped munitions and abandoned military hardware were seen scattered in the territory left by the Russian forces, images posted by the Ukrainian military showed.

These are key supply and logistics hubs that Russia depends on to restock its frontline positions in the east and military observers have said their capture by Ukraine would be a serious blow to Moscow’s military ambitions in Kharkiv.

Ukrainian officials this weekend hailed the “astonishing” pace of the counteroffensive and on Sunday, the country’s foreign minister used the momentum to appeal to Western allies for more stockpiles of sophisticated weapons.

“Weapons, weapons, weapons have been on our agenda since spring. I am grateful to partners who have answered our call: Ukraine’s battlefield successes are our shared ones,” Dmytro Kuleba said.

“Prompt supplies bring victory and peace closer,” his statement on social media read.

The Russian military, meanwhile, made the surprise announcement on Saturday that it was “regrouping” its forces from Kharkiv to the Donetsk region just south to focus its military efforts there.

But the announcement came soon after Moscow also said it was actually sending reinforcements towards Kharkiv.

In an awkward attempt to save face, the Russian Defence Ministry said on Saturday the troops’ withdrawal from Izyum and other areas in the Kharkiv region was intended to strengthen Russian forces in the neighbouring Donetsk region to the south.

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Ukraine parades destroyed Russian tanks and guns in Kyiv ahead of Independence Day

Ukraine parades destroyed Russian tanks and guns in Kyiv ahead of Independence Day

The retreat drew angry comments from Russian military bloggers and nationalist commentators, who bemoaned it as a major defeat and urged the Kremlin to respond by stepping up war efforts. Many scathingly criticised Russian authorities for continuing with fireworks and other lavish festivities in Moscow that marked a city holiday on Saturday despite the debacle in Ukraine.

A pro-Moscow separatist leader in the east of the country said there were “difficult” battles ongoing in the Donetsk region.

Russia and US clash over West’s weapons for Ukraine

Around Balakliya, one of the first towns to be recaptured by Ukrainian troops, journalists saw evidence of fierce battles, with buildings destroyed or damaged and streets mainly deserted.

Iryna Stepanenko, 52, who was outside cycling for the first time in months, said she had hidden in her basement for three months.

“There was a lot of fear, shelling. It was scary,” she recounted of the Russian takeover and Ukraine’s bid to recapture the town, where some 27,000 people lived before the invasion.

She said she was relieved to see Kyiv’s forces retake the town but was still worried about the future.

“I’m worried the Russians could return. I’m worried the shelling could start again.”

Despite the reported Ukrainian gains, Russian forces have continued bombardments across the frontline, and in the Donetsk region, officials said shelling killed 10 people and wounded another 19.

In the eastern Donetsk region, rebel leader Denis Pushilin said the situation in the town of Lyman was “very difficult” and that there was also fighting in “a number of other localities”, particularly in the northern part of the region.

German Foreign Minister Annalena Baerbock arrived in Kyiv on Saturday for a surprise visit, which she said was to demonstrate Berlin’s support for Ukraine.

It came a week after Ukrainian Prime Minister Denys Shmyhal’s trip to Berlin where he repeated Kyiv’s call for weapons.

Baerbock pledged continued “deliveries of weapons, and with humanitarian and financial support”.

Shmyhal on Saturday also criticised a “passive attitude” by the International Monetary Fund towards Ukraine’s request for aid to help its economy, which has been badly hit by the Russian invasion.