MOSCOW (Reuters) - Greece granted Russia the right to use its airspace for humanitarian flights to Syria on Aug. 31, TASS news agency quoted a Russian embassy official in Athens as saying on Wednesday. The Russian agency added that the request covered the period from Sept. 1 to Sept. 24. Separately, Russia's Interfax news agency quoted a Russian embassy official in Tehran as saying Iran had approved all of Moscow's requests on flights delivering humanitarian aid to Syria. (Writing by Gabriela Baczynska; Editing by Alexander Winning)