Fighting has intensified in Ukraine since Moscow launched a new offensive in the Kharkiv region on May 10, where Russian forces are thought to have captured around 13 settlements and 116 square miles of land.

Since the offensive began, Ukraine has regularly reported Russian casualties figures of more than 1,000 deaths per day.

After initial Russian successes, Ukraine has claimed to have stabilised the new frontlines.

In the Ukrainian city of Vovchansk, just three miles from the Russian border, Moscow’s forces have been bogged down in vicious combat since the first few days of the May 10 assault.

Ukrainian forces in the area have claimed that the fighting is “hotter” than Bakhmut — the city captured by Russian Wagner mercenaries in May 2023 after a brutal 10-month siege.

The Kharkiv offensive has also drawn Ukrainian resources away from other areas, leading to small but steady Russian advances across the rest of the 600-mile front line.

Andrei Belousov, the Russian defence minister, said on Friday that Russia had made advances “in all tactical directions”.

On Sunday, the Russian defence ministry claimed it had captured the village of Umanske and three other settlements in the Donetsk region.

In response to the renewed Russian advances, Joe Biden last week gave Ukraine permission to use US-made weapons inside Russia on troops massing for operations in Ukraine.

Russian sources on Sunday claimed American-made Himars missiles had been used in strikes on Russian troops in Belgorod, Russia.