Ukrainian military officials say Russian forces are attempting to infiltrate Kupiansk while disguised as civilians.

Kupiansk in Kharkiv Oblast has become one of the war’s most contested frontline cities in recent months.

Small sabotage and reconnaissance teams, usually two to five soldiers, move through the city trying to avoid detection, according to Viktor Trehubov, spokesperson for the operational-strategic formation “Dnipro,” RFE/RL reports.

“They attempt to use their numbers to slip through Ukrainian positions and later occupy buildings,” Trehubov said.

Ukrainian forces reportedly destroy Russian units before they can reach residential areas, to prevent them from establishing a foothold in the city.

Trehubov added that Russian troops continue to strike Kupiansk with artillery, drones, and other weapons.

Kupiansk has seen repeated attacks in recent months. Russian forces regularly target the city’s infrastructure and military positions. Ukrainian authorities say civilians remain under constant threat from shelling and infiltration attempts.

Russian forces have been conducting a year-long assault to capture the city, which serves as a critical logistics center and potential launching point for further attacks toward Kharkiv. 

The city now lies 90% destroyed with fewer than 1,700 civilians remaining from its original population, as Russian forces strike it daily with glide bombs, artillery, and drones.

The ISW warns that Russian advances near Kupiansk may soon threaten the city’s main supply route, as Moscow pursues a strategy of gradual encirclement rather than frontal assault.