Russia is forming a grouping of forces north of the city of Kharkiv, Governor Oleh Syniehubov said on national television on May 8.
Moscow recently intensified attacks against Kharkiv, which had a population of 1.4 million in 2021, with the use of missiles, glide bombs, and drones, destroying energy infrastructure and killing civilians.
Russian forces failed to take Kharkiv in the first weeks of the full-scale invasion despite the fact that the city lies less than 30 kilometers from the Russian border.
Russia "would need years" to occupy Kharkiv, Oleksandr Pivnenko, a commander of Ukraine's National Guard, said amid the looming threat of renewed attack.
The authorities are "closely monitoring" the northern direction, as Russian troops have resumed active assault operations east of Kharkiv after military units' rotation, the governor said.
"However, they still have no success. Yes, the enemy is indeed forming a certain grouping of troops. We will analyze further in case of possible attacks from the north," Syniehubov reported.
All the necessary measures are being taken to counteract "the challenges that may arise," he said.
In late March, President Volodymyr Zelensky said another major Russian offensive may come at the end of May or in June.
The Financial Times reported on April 13 that Russia might plan to attack Kharkiv as part of a wider offensive. Western officials nevertheless believe that Moscow does not have the capability to launch a new attack "without a major replenishment of Russian troops," according to Bloomberg.
At the end of March, Russia destroyed all the electrical substations in Kharkiv, leaving Ukraine's second-largest city without a stable power supply.