KYIV (Reuters) - Ukrainian President Volodymyr Zelenskiy said his troops are not giving up positions in Sievierodonetsk, a city where some of the war's biggest ground battles have been taking place.

       "Our heroes do not give up positions in Sievierodonetsk. In the city, fierce street fighting continues," Zelenskiy said in his nightly video address on Monday.

       Referring to the broader industrial Donbas region where Sievierodonetsk is located, Zelenskiy said: "And the Ukrainian Donbas stands, stands strong."

       (Reporting by Oleksandr Kozhukhar; Writing in Melbourne by Lidia Kelly; Editing by Leslie Adler)