Ukraine's President Volodymyr Zelenskiy self-records a video in front of a sign that reads 'Kupiansk’, amid Russia's attack on Ukraine, in the frontline town of Kupiansk, Kharkiv region, Ukraine December 12, 2025. Ukrainian Presidential Press Service/Handout via REUTERS
Ukrainian serviceman camouflages an HMMWV (Humvee) vehicle, amid Russia's attack on Ukraine, near the frontline town of Kupiansk, Ukraine December 12, 2025. REUTERS/Stringer
Anti-drone nets erected over a road amid Russia's attack on Ukraine, near the frontline town of Kupiansk, Ukraine, December 12, 2025. REUTERS/Stringer
A road sign reads 'Kupiansk region’, amid Russia's attack on Ukraine, near the frontline town of Kupiansk, Ukraine November 12, 2025. REUTERS/Stringer
A Ukrainian serviceman checks the sky for Russian combat drones as he stands at a road, amid Russia's attack on Ukraine, near the frontline town of Kupiansk, Ukraine November 12, 2025. REUTERS/Stringer
Ukrainian serviceman camouflages an HMMWV (Humvee) vehicle, amid Russia's attack on Ukraine, near the frontline town of Kupiansk, Ukraine November 12, 2025. REUTERS/Stringer

By Yuliia Dysa

KYIV, Dec 12 (Reuters) - Ukrainian forces said they had retaken parts of the northeastern town of Kupiansk and had encircled Russian troops there as President Volodymyr Zelenskiy visited the area and praised the operation, saying it strengthened Ukraine diplomatically.

With U.S.-backed peace efforts underway, Moscow has said it is advancing on all fronts and that it has seized Kupiansk and the strategic city of Pokrovsk in the east. Kyiv has denied this, saying that the fighting is continuing.

In a video clip posted on his social media account on Friday, Zelenskiy, wearing a bulletproof vest, is seen standing in front of a sign bearing the town's name at the entrance to Kupiansk.

"Today it is extremely important to achieve results on the front lines so that Ukraine can achieve results in diplomacy," Zelenskiy said in the clip.

RUSSIANS IN KUPIANSK 'COMPLETELY CUT OFF', KYIV SAYS

Ukraine's Khartiia Corps of the National Guard said it had liberated several northern districts of Kupiansk.

Russian supply routes have been cut off and several hundred Russian troops are surrounded, Khartiia said on the Telegram messaging app.

Reuters could not immediately verify the battlefield reports.

"Today, we can say that the Russians in the city are completely cut off. For a long time, they couldn't understand what was happening. But now they know they are surrounded," Ihor Obolienskyi, Khartiia's commander, was quoted by the Ukrainska Pravda news outlet as saying.

Russia, which began its full-scale invasion of Ukraine in February 2022, did not immediately comment on the Ukrainian assertions.

Ukraine's Deep State battlefield mapping project now shows at least three villages to the north and west of Kupiansk under Ukrainian control.

Kupiansk's northern districts are also shown as being under Ukrainian control, and the map suggests Russian troops are encircled in the city centre.

Military analysts said that in November, the pace of Russian advances had picked up to its highest this year as troops moved forward, taking control of smaller villages.

Russia said on Thursday it had captured the eastern town of Siversk. Kyiv said it remained under Ukrainian control.

(Reporting by Yuliia Dysa; Editing by Alison Williams, Timothy Heritage and Gareth Jones)