“(Ukrainian) military units have penetrated 50km beyond the enemy lines,” said Oleksiy Gromov, a senior official in the Ukrainian armed forces.

“During active operations in the Kharkiv area, more than 20 settlements have been liberated.

Ukrainian president Volodymyr Zelensky said on Wednesday his forces had recaptured several settlements in the Kharkiv region but did not give their names.

The city of the same name – the second largest in Ukraine – is regularly bombarded but Russian troops have never managed to seize it.

Gromov said more than 700 square kilometres had been recaptured in the Kharkiv area.

Ukraine is also carrying out a counteroffensive on the southern front, including towards the Russian-held city of Kherson.

Gromov said Kyiv’s troops had advanced “deep into the enemy’s defences, defences from two to several dozens of kilometres” in the south.

“A number of settlements have been recaptured,” he added, without giving details.

Ukrainian troops also claimed gains in the eastern Donbas region, including around Kramatorsk and Sloviansk.