Russia did not immediately respond to Zelensky’s claims, but its defence ministry said earlier on Thursday that Russian forces had blocked Ukrainian attempts to take several other communities.
The surprise Ukrainian incursion has reframed the war and caused chaos in the Kursk region, leading to the evacuation of more than 120,000 civilians, according to Russian authorities, and the capture of at least 100 Russian troops, according to Kyiv.
Zelensky has said one of the reasons for the incursion was to protect neighbouring Ukrainian regions.
“The more Russian military presence is destroyed in the border regions, the closer peace and real security will be for our state. The Russian state must be responsible for what it has done,” he said on Tuesday.
Russia has seen previous raids of its territory in the war, but the Kursk incursion is notable for its size, speed, the reported involvement of battle-hardened Ukrainian brigades, and the length of time they have stayed inside Russia.
As many as 10,000 Ukrainian troops are involved, according to Western military analysts. It is the first time foreign troops have invaded and held Russian territory since Nazi Germany did in World War II.
Although Russian military bloggers report that Russian reserves sent to the Kursk region have slowed Ukrainian advances, questions remain over whether the incursion might force Moscow to move troops to Kursk from front-line positions in eastern Ukraine, where they have made slow but steady advances this year.
White House national security spokesman John Kirby said on Thursday that Russia had withdrawn some forces, including infantry units, from Ukraine and was shifting them to Kursk, but that the US did not know how many troops were involved.
However, a US official who spoke on the condition of anonymity because they were not authorised to comment publicly said it does not appear that Russia has moved a sufficient number of armoured battalions or other types of combat power from the front-line in Ukraine to the Kursk region, and that Moscow will need to shift more troops to repel Kyiv’s forces.
As of Thursday, the Ukrainian military claimed to hold more than 80 towns and settlements in the Kursk region.
Russian military bloggers reported that Ukrainian small mechanised groups have continued to probe Russian defences. And satellite images analysed by Associated Press on Thursday show that a Ukrainian drone attack on Russian airbases damaged at least two hangars and other areas.
Images taken Wednesday by Planet Labs PBC show that two hangars at Borisoglebsk Air Base had been struck, with a field of debris around both. It was not immediately clear what purpose the hangars served. There also appeared to be potential damage to two fighter aircraft at the base.
Separately, at Savasleika Air Base, one burn mark could be seen just off the runway in images Wednesday, though there was no apparent damage to the fighter planes and other aircraft there.
Kursk’s acting Governor Alexei Smirnov on Thursday ordered the evacuation of the Glushkovo region, about 45km (28 miles) northwest of Sudzha. The order suggests that Ukrainian forces were gradually advancing toward the area.
At a facility receiving evacuees, Tatyana Anikeyeva told Russian state television about her ordeal fleeing from the fighting. “We were rushing from Sudzha … We hid in the bushes. Volunteers were handing out water, food, bread to people on the go. The sound of the cannonade continued without any break. The house was shaking.”
Evacuees milled around and waited in long lines for food and other supplies. One man stroked his pet dog and tried to comfort her, while saying that he felt nauseous and had no appetite.
Russia also declared a federal-level state of emergency in the Belgorod region, a day after a regional-level declaration was made for the area. The change in status suggests that officials believe the situation is worsening and hampering the region’s ability to deliver aid.
Ukraine’s chief military officer, General Oleksandr Syrskyi, said earlier this week that Ukrainian forces had taken 1,000 sq km (about 390 square miles) of the Kursk region, though his claim could not be independently verified.
The contact lines in Kursk have remained fluid, allowing both sides to manoeuvre easily, unlike the static front line in eastern Ukraine where it has taken Russian forces months to achieve even incremental gains.
Russian officials have pushed back on Syrskyi’s territorial claim.
“What’s happening in Kursk is the incursion of terrorist sabotage groups, so there is no front line as such,” Russia’s deputy UN ambassador, Dmitry Polyansky, told reporters on Wednesday. “There is an incursion because there are forests that are very difficult to control.”
Polyansky called the incursion an “absolutely reckless and mad operation”, and said Ukraine’s aim to force Russia to move its troops from eastern Ukraine is not happening because “we have enough troops there”.
Sudzha has a measuring station for Russian natural gas that flows through Ukrainian pipelines and accounts for about 3 per cent of Europe’s imports. There has been no indication of any disruption to the gas flow.