Kharkiv (Ukraine) (AFP) -
Ukrainian forces said Saturday they had entered Kupiansk in eastern Ukraine dislodging Russian troops from a key logistics hub in a lightning counter-offensive that has seen swathes of territory recaptured.
The German foreign minister, Annalena Baerbock, meanwhile arrived in the Ukrainian capital for a surprise visit, which she said was to demonstrate Berlin's support for Ukraine in its battle against Russia.
Ukrainian special forces published images on social media showing camouflage-clad officers with automatic weapons 'in Kupiansk'. It 'was and will always be Ukrainian,' their statement said.
The town of some 27,000 people, that sits on a crucial supply route for Russia forces in the east, fell within the first week after the Kremlin ordered its invasion of Ukraine on February 24.
Observers of the conflict expect Ukrainian forces to announce further gains in the Kharkiv region, which borders Russia, and has been either controlled by Russia or shelled by its artillery for months.
- 'Astonishing' advance -
There was no official confirmation that Kyiv's troops had also routed Russian forces from Iyzum -- an important staging ground for Russia's war effort -- with a pre-war population of around 45,000 people.
But images flooding social media appeared to show Ukrainian forces within the city and Russian observers of the conflict said there were initial reports Moscow's army had already withdrawn.
'Ukrainian troops are advancing in eastern Ukraine, liberating more cities and villages. Their courage coupled with Western military support brings astonishing results,' foreign ministry spokesman Oleg Nikolenko said in a statement on social media.
'It's crucial to keep sending arms to Ukraine. Defeating Russia on the battlefield means winning peace in Ukraine,' he added.
His assessment of the pace of the Ukrainian gains came after President Volodymyr Zelensky announced late Friday that his troops had retaken some 30 towns and villages in the northeastern Kharkiv region as part of the sweep.
Ukraine's push appears to have caught Russian troops largely off guard.
The head of the Russian-installed administration of the Izyum told state news agency RIA Novosti that the situation in the region was 'very difficult'.
'For the past two weeks, the city has been targeted by bombardments by Ukrainian forces... which is causing serious destruction and causing many deaths and injuries,' Vladislav Sokolov told RIA Novosti.
Moscow on Friday made the surprise announcement it was dispatching reinforcements to Kharkiv, with images on state media showing tanks and artillery and support vehicles moving in columns on dirt roads.
- 'It was frightening' -
The capture of urban hubs like Kupiansk and Izyum would be a significant blow to Russia's ability to effectively resupply positions on the eastern frontline and could see Russia pushed back from Kharkiv entirely.
In one village captured by the advancing Ukrainians, electric pylons were toppled and cables lay across the ground and houses were gutted, AFP journalists reported.
'It was frightening,' said 61-year-old Anatoli Vasiliev recalling the battle earlier this week that saw Ukrainian forces recapture the village from the Russians.
'There were bombings and explosions everywhere.'
Ukrainian troops were also advancing along portions of the southern front line, a spokesperson said Saturday, in some regions by dozens of kilometres, into territory captured by Russian troops at the beginning of the invasion.
Russian news agencies meanwhile reported six large explosions in Nova Kakhovka, a town held by Russian troops in the southern Kherson region.
- 'We will stand by Ukraine' -
Baerbock was in Kyiv Saturday for her second trip to Ukraine, which comes a week after Ukrainian Prime Minister Denys Shmygal's trip to Berlin where he had repeated Kyiv's call for weapons.
'I have travelled to Kyiv today to show that they can continue to rely on us. That we will continue to stand by Ukraine for as long as necessary with deliveries of weapons, and with humanitarian and financial support,' she said.
Over the last weeks, Germany has sent howitzers, rocket launchers and anti-aircraft missiles to Kyiv, part of an arsenal of Western-supplied weapons that observers say have hurt Russia's supply and command abilities.
Baerbock's visit comes on the heels of a trip from US Secretary of State Antony Blinken who promised a nearly $3 billion military package for Ukraine.
In a meeting in Brussels with NATO Secretary General Jens Stoltenberg, Blinken said Russia's push to send reinforcements showed Moscow was paying 'huge costs' in its bid to capture and then hold Ukrainian territory.
However, Russian forces were still inflicting serious damage with a campaign of shelling in Kharkiv city and in the industrial region of Donbas in the east.
Oleg Synegubov, the head of the Kharkiv region, said Russian shelling had left 14 civilians injured.
Pavlo Kyrylenko, the head of the Donetsk region, which is part of Donbas, said Russian shelling had left two dead.