(FILES) This file photo taken on October 7, 2015 shows chairman and CEO of US oil and gas corporation ExxonMobil, Rex Tillerson, speaking during the 2015 Oil and Money conference in central London. President-elect Donald Trump on December 13, 2016 tapped ExxonMobil chief Rex Tillerson, an oilman with deep ties to Russia, as his secretary of state. Tillerson's nomination comes just days after a secret CIA report accused Russia of interfering with the US election in favor of Trump, in a development which could complicate his confirmation. / AFP PHOTO / BEN STANSALL