Ukrainian troops are fighting to keep control of the northwestern and southeastern parts of the town of Lyman, the country's defence ministry said on Friday, as Russia's offensive in east Ukraine gathers pace.

Ukrainian troops were "counteracting attempts" by Russia to push its offensive towards the key Ukrainian town of Sloviansk, defence ministry spokesman Oleksandr Motuzyanyk said at a briefing.

(Reporting by Natalia Zinets, writing by Max Hunder; Editing by Hugh Lawson)