HONG KONG, Aug 20 (Reuters) - China’s top legislature has postponed a vote on extending an anti-sanctions law to Hong Kong, the South China Morning Post said on Friday, citing sources. Beijing was expected to formally approve the law for the Chinese-ruled city on Friday and then leave Hong Kong officials to decide if the measure should be amended for the global financial hub. Reporting by Anne Marie Roantree; Editing by Clarence Fernandez Our Standards: The Thomson Reuters Trust Principles.