KYIV - Ukrainian forces are engaged in a "fierce defence" of the eastern city of Sievierodonetsk, which is two-thirds surrounded by Russian forces, the Luhansk region's governor said on Friday, citing the head of the city's administration.

Shelling, which is "very strong", has damaged 90% of the housing in the city, Serhiy Gaidai added, also citing Oleksandr Stryuk.

(Reporting by Natalia Zinets; Writing by Conor Humphries; editing by John Stonestreet)