Moscow’s forces captured five villages in a renewed ground assault in northeastern Ukraine, the Russian Ministry of Defence has said, as journalists in the city of Vovchansk described multiple buildings destroyed after Russian air raids.

Ukrainian officials on Saturday did not confirm whether Russia had taken the villages, which lie in a contested “grey zone” on the border of Ukraine’s Kharkiv region and Russia.

Ukrainian journalists reported that the villages of Borysivka, Ohirtseve, Pylna and Strilecha were taken by Russian troops on Friday.

Russia said the village of Pletenivka was also taken.

In an evening statement Saturday, Ukrainian President Volodymyr Zelenskyy said fighting was continuing in Strilecha and Pletenivka, as well as Krasne, Morokhovets, Oliinykove, Lukyantsi and Hatyshche.

“Our troops are carrying out counterattacks there for a second day, protecting Ukrainian territory,” he said.

On Friday, the Institute for the Study of War said that geolocated footage confirms at least one of the villages was seized. The Washington-based think tank described recent Russian gains as “tactically significant”.

The renewed assault on the region has forced more than 1,700 civilians residing in settlements near the fighting to flee, according to Ukrainian authorities. It comes after Russia stepped up attacks in March targeting energy infrastructure and settlements, which analysts predicted were a concerted effort by Moscow to shape conditions for an offensive.

On Saturday, Russia continued to pummel Vovchansk with air raids and rockets as police and volunteers raced to evacuate residents. At least 20 people were evacuated to safety in a nearby village. Police said that 900 people had been evacuated the previous day.

Journalists from The Associated Press news agency who accompanied an evacuation team described empty streets with multiple buildings destroyed and others on fire. The road was littered with newly made craters and the city was covered in dust and shrapnel with the smell of gunpowder heavy in the air. Mushroom clouds of smoke rose across the skyline as Russian jets conducted multiple air attacks.

The AP journalists witnessed nine air attacks during the three hours they were there.

“The situation in Vovchansk and the settlements along the border [with Russia] is incredibly difficult. Constant aviation attacks are carried out, multiple rocket missile systems strikes, artillery strikes,” said Tamaz Hambarashvili, the head of the Vovchansk military administration.

“For the second day in a row, we evacuated all the inhabitants of our community who are willing to evacuate,” he said.

“I think that they are destroying the city to make [local] people leave, to make sure there are no militaries, nobody. To create a ‘grey’ zone.’”

Russia’s recent push in Kharkiv seeks to exploit ammunition shortages before promised Western supplies can reach the front line and pin down Ukrainian forces in the northeast and keep them away from heavy battles under way in the Donetsk region where Moscow’s troops are gaining ground, analysts said.

Russian military bloggers said the assault could mark the start of a Russian attempt to carve out a “buffer zone” that President Vladimir Putin pledged to create earlier this year to halt frequent Ukrainian attacks on Belgorod and other Russian border regions.

The governor of Russia’s Belgorod region, which borders Ukraine, said on Saturday that one woman was killed and 29 people were wounded, including a child, in shelling by Ukraine’s armed forces.

Meanwhile, Ukrainian officials have downplayed Russian statements about captured territory, with reinforcements being rushed to the Kharkiv region to hold off Russian forces.

On Telegram, Kharkiv regional governor Oleh Syniehubov said that heavy fighting continued in the areas around Borysivka, Ohirtseve, Pylna and Oliinykove, but that the situation was under control and there was no threat of a ground assault on the city of Kharkiv.

In the meantime, artillery, mortar and aerial bombardments hit more than 30 different towns and villages in the region on Saturday, killing at least three people and injuring five others, Syniehubov said.