By Pavel Polityuk and Maria Starkova KYIV/LVIV/MARIUPOL, Ukraine (Reuters) -Russian missile strikes hit Ukraine’s capital Kyiv and other cities on Saturday, as Moscow said its troops had cleared the urban area of Mariupol and only a small contingent of Ukrainian fighters remained inside a steelworks in the besieged southern port. Russia’s claim to have all but taken control of Mariupol, scene of the war’s heaviest fighting and worst humanitarian catastrophe, could not be independently verified. It would be the first major city to have fallen to Russian forces since the Feb. 24 invasion. “The s…