The mayor of Severodonetsk in the eastern Ukrainian region of Luhansk has admitted that the city is now under full occupation by Russia.

A Ukrainian news agency reports that Mayor Oleksandr Stryuk made the remark on Saturday. He expressed hope that Ukrainian forces will recapture the city at the earliest date possible.

The mayor added that Ukrainian troops have not been besieged by Russian forces as they already withdrew from the city.

He suggested that Ukrainian forces will continue their resistance and seek to gain an upper hand by fighting from higher ground in the city of Lysychansk, which neighbors Severodonetsk across a river.

Russia announced full control of the city, and is trying to take all of Luhansk. It says its forces have moved to Lysychansk from the south and that street battles began in the city on Saturday.

The Russian defense ministry said on Saturday that its forces launched a missile attack on the eastern Ukrainian region of Donetsk.

Missile attacks were also confirmed in Ukraine's north and west on the same day. The mayor of Zhytomyr said 24 missiles were launched by aircraft that came from the direction of Belarus.

The Ukrainian military says 20 missiles were fired on the northern region of Chernihiv, with some launched by planes that entered from the direction of Belarus.

Ukraine's military intelligence agency says the missiles were fired by Russian bombers and that this is the first airstrike launched from the airspace of Belarus, an ally of Russia.