By Pavel Polityuk KYIV (Reuters) -Ukrainian defenders battled on Saturday to contain Russian forces along several fronts, officials said, as the United States urged China to align itself with the West in opposing the invasion following an ill-tempered G20 meeting. A missile strike on the northeastern city of Kharkiv wounded three civilians, its governor said, though Russia’s main attacks appeared focused southeast of there in Luhansk and Donetsk. Those two provinces, parts of which were held by pro-Russian separatists before the conflict began in February, comprise the eastern industrial regio…