Ukrainian commander reveals how the Kupiansk operation began

On Dec. 17, the Russian dictator once again claimed that his forces had taken control of Kupiansk, a city in eastern Ukraine’s Kharkiv Oblast. At the very moment Putin was saying this in Moscow, the supposed “liberators” had already been encircled for several days in central Kupiansk and were losing manpower under sustained, methodical strikes by Ukrainian units.

“Kupiansk is currently blocked. An operation to identify and eliminate the enemy is underway directly inside the city,” Col. Serhii Sidorin, commander of the search-and-strike group of the National Guard’s 2nd Corps, Khartiia, who is personally overseeing the liberation of the city, told NV.

The Kupiansk operation became an unexpected and highly publicized success for Ukraine’s Defense Forces against the backdrop of heavy, prolonged fighting in the east that has continued throughout the year. Effective actions by the Khartiia corps in a city that Putin had turned into a near-symbol of his occupying army’s supposed success became known on Dec. 12. Since then, the Russian position there has only deteriorated.

According to Sidorin, the remaining occupying forces are concentrated in the city center, in high-rise buildings and several standalone structures. Up to 100 enemy soldiers may still be there, mostly without communications or supplies, and some are wounded. Ukrainian forces maintain constant aerial surveillance of these remnants using drones and regularly strike them with fire.

After Putin’s latest statements, Sidorin expects Russia to intensify attempts to unblock its encircled troops and to plant flags at selected points for video footage and subsequent propaganda claims. In reality, however, the encirclement ring continues to shrink, tightening around the enemy, said the colonel, who is observing the operation directly on the ground.

An operation kept quiet

The Kupiansk axis became one of the key flashpoints on the eastern front in autumn 2025. Russian forces sought to encircle the city, using it as a stronghold to apply pressure along the Oskil River and threaten Ukraine’s defenses in northern Kharkiv Oblast.

By November, enemy units had captured several settlements on the approaches to the city — Kindrashivka, Radkivka, Tyshchenkivka and Myrne — which would have allowed Russia to establish an outer defensive ring and block Ukrainian forces.

“It was obvious that the enemy intended to encircle Kupiansk and block the movement of our units, both for logistics and for combat operations,” Sidorin told NV.

To preempt the enemy, Ukrainian command decided to launch an operation to liberate these settlements and push Russian forces back to the Oskil River. Units involved included the 13th Khartiia Brigade, the 475th Assault Regiment Code 9.2, the 92nd Assault Brigade, the Defense Intelligence Directorate’s International Legion and the 144th Mechanized Brigade.

Initially, Sidorin said, planning was carried out and areas of responsibility were assigned among the units forming the search-and-strike group. The main focus was on settlements most critical to the enemy, primarily Radkivka and Kindrashivka. During combat, plans were adjusted based on enemy behavior.

“In some areas the enemy resisted, in others they didn’t engage at all and withdrew. In some places we encircled them and gradually destroyed them; in others we didn’t even enter — we eliminated them using drones or other robotic systems,” the colonel said, describing Ukrainian tactics.

One of the main challenges was Russia’s use of underground infrastructure. An international gas pipeline running north of Kupiansk and beneath the Oskil River became a concealed route for enemy infiltration.

“The enemy is making maximum use of this pipeline because it allows them to move covertly in sufficient numbers and get very close to the city,” Sidorin said.

The pipeline enables Russian invaders to cross the water obstacle unnoticed. As of December, however, all exits from the pipeline have been identified and placed under fire control, he said.

Engineering solutions such as completely destroying the pipeline proved ineffective, Sidorin noted. The network’s length allows the enemy to bypass damaged sections, surface elsewhere and then go back underground. As a result, the final stage of the Kupiansk liberation has taken on the character of a prolonged urban clearance operation with elements of counter-engineering warfare.

In addition to the pipeline, Russian forces continue attempts to cross the Oskil by boat, but these are detected remotely and usually destroyed by drones.

The area near the village of Holubivka, located in lowlands north of Kupiansk, is strategically important because one of the pipeline exits lies west of it. However, occupying the settlement itself is unnecessary, Sidorin said; tactically, it is more advantageous to keep it under surveillance and fire control.

Fighting in Kupiansk is further complicated by an extremely high concentration of enemy FPV drones, he added. This sharply complicates logistics, evacuation and rotation, slowing operations even under otherwise favorable conditions.

Ukrainian forces are currently conducting both defensive operations in Kupiansk — blocking cleared areas from enemy infiltration — and active search-and-strike missions to liberate city neighborhoods.

In Sidorin’s view, the key factors behind Ukraine’s success in Kupiansk were adherence to the plan, clear coordination among units and strict information silence.

“Some media outlets, if they had known, might have reported it prematurely to create a sensation,” he said.

But troops and commanders maintained that silence.

One of the first allowed to break it was the Ukrainian president.

On Dec. 12, President Volodymyr Zelenskyy personally visited Kupiansk and recorded a video there. Today, he said that the visit influenced talks with European and U.S. partners, helping them understand that Putin is lying about the current situation on the front line.