(Reuters) - Air raid sirens were heard across most Ukrainian cities early on Saturday morning urging people to seek shelters, local media reported.

       Sirens were heard in the capital city of Kyiv, the western city of Lviv in Odessa, and Kharkiv, Cherkasy, as well as in the Sumy region in northeast of the country, a number of local Ukrainian media reported.

       Russian forces appeared to be regrouping on Friday for a possible assault on Kyiv, with satellite images showing them firing artillery as they closed in on the capital.

       (Reporting in Melbourne by Lidia Kelly; Editing by Michael Perry)