KYIV, Ukraine — Western defense officials and analysts said Saturday they believed Ukraine had breached Russian front lines south of the country’s second-largest city, taking thousands of square kilometers of territory and threatening to cut Russian supply lines.
The UK Ministry of Defence, in an online briefing, said it believed the Ukrainians had advanced up to 50 kilometers (30 miles) south of Kharkiv in northeastern Ukraine.
The advance appears to be around Izyum, long concentrated on the Russian front line and the site of heavy artillery and other fighting. The British described the Russian forces around Izyum as “increasingly isolated”.
“Russian forces were probably taken by surprise. The sector was only lightly held and Ukrainian units captured or surrounded several towns,” the British military said.
He added that the nearby town of Kupyansk also appeared to be under pressure from Ukrainian forces and that its loss would significantly affect Russian supply lines in the area.
An image shared on social media on Saturday appears to show Ukrainian soldiers outside a main government building in Kupiansk, about 73 kilometers (45 miles) north of Izyum.
The image showed soldiers waving the flag of Ukraine’s 92nd Separate Mechanized Battalion in front of a building that resembled the Kupiansk City Council building, which sits just along the Oskil River.
The Ukrainian military has yet to acknowledge entering the city, although it comes amid days of apparent Ukrainian gains south of Kharkiv.
A Washington-based think tank also referred to sizable Ukrainian gains on Saturday, estimating that Kyiv seized about 2,500 square kilometers (965 square miles) in its push into the northeast.
The Institute for the Study of War said in a report that it appeared “disorganized Russian forces (were) caught up in Ukraine’s rapid advance”. They cited social media images of apparent Russian prisoners seized during the advance around Izyum and surrounding towns.
The same report said Ukrainian forces “could collapse Russian positions around Izyum if they cut Russian land lines of communication” north and south of the city.
The fighting in the east comes amid an ongoing offensive around Kherson in southern Ukraine. Analysts suggest that Russia may have taken soldiers from the east to reinforce around Kherson, giving the Ukrainians an opportunity to strike at a weakened front line.
Ukraine’s military has been more circumspect about reported gains, saying in its regular update on Saturday that it has taken “more than 1,000 square kilometers” (386 square miles) from pro-Kremlin forces since launching its counter-attack. long-awaited offensive this week.
He said “in some areas Defense Force units penetrated enemy defenses to a depth of 50 kilometres”, matching the British assessment, but did not divulge any geographical details.
Kyiv officials have been tight-lipped for weeks over their counteroffensive plans to retake territory invaded by Russia at the start of the war, calling on local residents to refrain from sharing information on social media for fear of jeopardize the current operation.
Moscow did not immediately acknowledge or comment on the claims made by Ukraine and its Western allies.
Elsewhere, Ukrainian emergency services reported that a civilian had been killed in a Russian missile strike in the Kharkiv region overnight.
The regional branch of the state Emergency Service said the body of a 62-year-old woman was found buried in the rubble of her home, which was flattened by the strike.
Regional Governor Oleh Syniehubov also accused Moscow of ramming into settlements taken over by Kyiv during its recent advances, as well as other residential areas in the region.
Syniehubov said in a Telegram post that five civilians were hospitalized in Izyum district, while nine others were injured elsewhere in the region.
In the besieged Donbass region south of Kharkiv, Ukraine’s governor says civilians were killed and injured overnight by Russian shelling near the town of Bakhmut, a key target of the blocked Russian offensive in that area . Pavlo Kyrylenko said on Telegram that two people died and two others were injured in Bakhmut and the nearby village of Yahidne.
Meanwhile, German Foreign Minister Annalena Baerbock arrived in Kyiv for an unannounced visit, saying Europe would not tire of helping Ukraine despite Russian President Vladimir Putin’s efforts to ratchet up the pressure by denying energy supply.
Baerbock said Germany would help Ukraine find and remove mines and other unexploded ordnance left by Russian troops in areas where they were pushed back by Ukrainian forces.