The Ukrainian military has said more than 17,000 Russian soldiers were killed in the first breakthrough for Putin's troops in months.
The capture of the city of Avdiivka in Ukraine’s eastern Donbas region was hailed as the first proper victory for Russia since the conquest of Bakhmut in May.
However, analysts said the cost for the Russian army includes 30,000 injured soldiers in the conflict.
Ukraine said it had withdrawn its soldiers to save troops from being fully surrounded after months of fierce fighting. Putin hailed the fall of Avdiivka as an important victory and congratulated Russian troops.
Avdiivka coke plant was taken by the Russians
Reuters
Ukrainian military spokesman Dmitry Likhovy said: "The losses of Russians around Avdiivka are colossal. My colleagues and I did the calculations and pulled up our archival records from the beginning of the year."
After the failure of Ukraine to pierce Russian lines last year, Moscow has been trying to grind down Ukrainian forces just as Kyiv ponders a major new mobilisation and President Volodymyr Zelenskiy appoints a new commander to run the war.
Russian forces on Monday claimed full control of the vast Soviet-era coke plant in Avdiivka, after a small faction of Ukrainian soldiers had holed themselves within the centre of the plant.
Russian state television showed blue-and-yellow Ukrainian flags being taken down in Avdiivka and Russia's white, blue and red tricolour flag raised, including over the coke plant.
LATEST DEVELOPMENTS
Avdiivka has been heavily shelled since the start of the invasion
Getty/3rd Assault Brigade / Handout/Anadolu via Getty Images
The US-based Institute for the Study of War said that Russian air superiority was a significant reason for its success in Avdiivka. It comes as a new row over ammunition supplies from the West has erupted.
Meanwhile, Ukrainian authorities said they had opened an investigation into alleged shootings by Russian forces of six unarmed Ukrainian soldiers in Avdiivka.
The prosecutors referred to information about "the execution of six prisoners" at a position in Avdiivka, adding that they were "seriously injured and awaiting evacuation."
It said the information had been shared on Telegram but did not name the source.
Some of the ruins in Avdiivka
Getty
Ukrainian public broadcaster Suspilne quoted Ukrainian military spokesperson Dmytro Lykhoviy as saying: "There is still no possibility to confirm or refute" the killings at Avdiivka, as an investigation was ongoing. However, he added it would not be the first time Russia had committed war crimes."
Russia has constantly denied committing war crimes since the start of the conflict in 2022.
At an international security conference in Munich, President Zelensky blamed a shortage of ammunition from the West for the fall of Avdiivka. He added: "If Trump (comes) to Ukraine, I am ready to go with him to the front line."
Denmark’s prime minister Mette Frederiksen also said that she would increase the number of artillery shells being sent to Ukraine.