LIBREVILLE (Reuters) - African Union mediators on Gabon's election crisis have delayed until further notice their mission to the country, which was due to have begun on Friday, Gabon's Foreign Minister Emmanuel Issoze Ngondet said on Thursday.

Chad's President Idriss Deby is the lead mediator but he returned tired from a G20 summit meeting of the world's top economies in China and so the visit has been delayed, he said. There was no immediate comment from Chad or the African Union.

(Reporting by Gerauds Wilfried Obangome; Writing by Matthew Mpoke Bigg; Editing by Louise Ireland)