Trump to announce Exxon chief Tillerson as secretary of state

US President-elect Donald Trump will announce Exxon-Mobil Corp's Rex Tillerson as his choice for secretary of state on Tuesday, a senior transition official has said.

Trump is to make the announcement on Tuesday morning, going with a business leader whose experience in diplomacy is from making deals with foreign countries for the world's largest energy company.

Trump picked Tillerson, 64, after the Texan was backed by several Republican establishment figures, including former secretary of state James Baker, former secretary of state Condoleeza Rice and former defence secretary Robert Gates, the transition official reportedly said.

Trump judged in making the pick that Tillerson could adequately address questions about his ties to Russia, an official said.

However, Tillerson's lack of experience and close ties to Russian President Vladmir Putin are reportedly raising concerns from senators of both parties.

Tillerson's company has long done business in Russia. He has known Putin since he represented Exxon’s interests in Russia during the regime of Boris Yeltsin. In what appears to be a sign of the close relationship, the Kremlin is said to have bestowed the country’s Order of Friendship decoration on Tillerson after he struck a 2011 deal that gave Exxon access to prized Arctic resources and allowed Russian state oil company OAO Rosneft to invest in Exxon concessions around the world.