Zelensky: Russia controls one fifth of Ukrainian territory

He said all Russian military formations ready to fight are involved in this aggression.

Russian forces have intensified attacks in the town of Severodonnetsk in the eastern region of Donbas, reports the BBC, broadcast Clankosova.tv.

Defence officials in the United Kingdom have said Russia has occupied most of the city.

Severodonnetssk is the most eastern city under Ukraine's control, and regional governor Serhiy Haidai said Russia was trying to break defence in the city from all directions.

However, he said Ukrainian troops were carrying out counterattacks, “ -- pushing the enemy back in some ways and taking some prisoners”.