On December 2, 2025, Russian President Vladimir Putin announced the "takeover" of Kupyansk in the Kharkiv region. Just days later, however, Ukrainian President Volodymyr Zelensky appeared on the outskirts of the city, and the Russian forces found themselves surrounded, News.bg reports.
According to officers and fighters from the assault units, quoted by the newspaper The Times, the operation near Kupyansk is the most successful for Ukraine since its invasion of the Russian Kursk region in 2024.
Journalists reveal that last year, after the breakthrough of Russian troops to Kupyansk, an operational group was secretly formed, commanded by 38-year-old Colonel Sergei Sidorin.
According to him, this group alone has destroyed or wounded at least 1,500 Russian servicemen, with the ratio being about 10 eliminated occupiers for one dead Ukrainian soldier. According to his estimates, no more than 50 Russian fighters remain in the area, barricaded in isolated areas around the city.
Russian units used an abandoned gas pipeline to appear behind the Ukrainian forces in the Kupyansk region. By mid-September, this maneuver had scattered several hundred occupiers throughout the city, which led to a critical situation.
Sidorin admits that there was a real risk of losing Kupyansk, which would have allowed Russia to build a new supply line for its troops in Donbass.
On September 21, the colonel was given three days to form a combat unit from units of the newly created 2nd Corps "Charter", which had not yet participated in combat operations.
„Everyone was new to each other. "True chaos," he says.
They were faced with a mechanized brigade and two motorized rifle regiments of Russia. Due to the lack of numerical superiority, the Ukrainian forces changed their tactics, adapting to the enemy's methods. The assault units were divided into small groups of eight infantrymen, which moved in different directions to disorient the enemy.
“We decided to act simultaneously in all directions - not openly, but secretly. Where we achieved success, we developed it,“, explains Sidorin.
The Russians failed to read the true intentions of the Ukrainian forces until it was too late. The main emphasis was on the use of drones to strike the enemy while the infantry advanced and cut off logistical routes.
The operation coincided with worsening weather conditions - low temperatures, rain and thick fog, which seriously hampered Russian intelligence.
The Times recalls that on October 29, Vladimir Putin ironically invited Western journalists to visit “occupied” Kupyansk. Until November 20, the Russian command apparently did not realize how compromised its positions were. When on December 2, Putin declared complete control over the city, his troops there were already effectively doomed.