Serhii said he did not want to leave because he was afraid of what might happen to their four goats.

As we surveyed the damage there was the screech of yet more glide bombs being released, followed by the heavy thud of the explosion.

Russia's air force is having an increasingly deadly effect, and for now Ukraine has no answer.

Ukrainian officials say Russia had the capability to aggravate the situation in border areas but not to capture the city of Kharkiv itself.

Reports suggest Moscow is hoping to create a 10km (six-mile) buffer zone for its Belgorod region, after a series of Ukrainian cross-border attacks.

In his nightly address on Saturday, Ukrainian President Volodymyr Zelensky said fighting was continuing in seven border villages, Reuters reported.

"Our defensive operations continue in the Kharkiv region", he said, adding the situation in Donetsk "remains especially tense".

• Seven dead in attack on Belgorod region

On Friday, the US announced a new $400m (£319m; €371m) military aid package for Ukraine.

It will be Washington's third instalment of aid to the country after months of political deadlock - adding to the previous package worth a total of $7bn sent in late April.

US Secretary of State Anthony Blinken said the "urgently needed" aid would include air defence munitions, artillery rounds, anti-tank weapons and armoured vehicles.

On Friday, National Security Spokesman John Kirby told reporters that Russia would "make further advances in the coming weeks to try and establish a buffer zone along the Ukrainian border".

Moscow has been looking to capitalise on the delayed arrival of US weaponry by continuing to push forwards in the eastern Donetsk region.

The return of heavy fighting in the north-east further illustrates Russia's growing ambitions.