U.S. President-elect Donald Trump is expected to name the chief executive of Exxon Mobil as the country's top diplomat, NBC News reported Saturday.

Exxon chief Rex Tillerson emerged on Friday as Trump's leading candidate for U.S. secretary of state and is expected to meet with him later on Saturday, a transition official told Reuters.

NBC News cited two sources close to the transition team in reporting that Tillerson will be named as secretary of state.

The president-elect had interviewed 2012 GOP nominee Mitt Romney twice – taking him to a three-Michelin starred dinner on one of those occasions.

Exxon chief Rex Tillerson (right) is expected to be named as the country's top diplomat

Trump is said to be snubbing Mitt Romney. The former Governor of Massachusetts was interviewed for the role twice. They are seen above having dinner in New York in November

Tillerson's favored status was revealed as former New York Mayor Rudy Giuliani formally withdrew from consideration for secretary of state.

Giuliani's withdrawal came after he was fully vetted by the Trump transition team for his overseas business ties in what was described by the Trump official as an 'intense' effort by lawyers and accountants.

Giuliani, who runs a global consulting firm, was given a clean bill of health, with Trump's aides concluding his business interests would not pose a risk to his confirmation.

Should Tillerson be nominated, his business ties, too, will come under scrutiny. Exxon Mobil has operations in more than 50 countries and boasts that it explores for oil and natural gas on six continents.

In 2011, Exxon Mobil signed a deal with Rosneft, Russia's largest state-owned oil company, for joint oil exploration and production. Since then, the companies have formed 10 joint ventures for projects in Russia.

In 2013, Russian President Vladimir Putin awarded Tillerson his nation's Order of Friendship.

'He has had more interactive time with Vladimir Putin than probably any other American with the exception of Henry Kissinger,' John Hamre, a deputy defense secretary to Bill Clinton told the Wall Street Journal.

But U.S. sanctions against Russia for its incursion into Crimea cost Exxon Mobil dearly, forcing it to scrap some projects and costing it at least $1 billion in losses. Tillerson has been a vocal critic of the sanctions.

Trump has spoken of wanting warmer relations with Moscow, which has sparked concerns in Congress that he could lift or loosen some of the sanctions on Russia.

Russia's Prime Minister Vladimir Putin speaks with Rex Tillerson in Sochi in 2011

Tillerson has been chairman and CEO of Exxon Mobil since 2006. He is expected to retire from the company next year.

Should Tillerson be nominated, climate change could be another divisive issue. The company is under investigation by the New York Attorney General's Office for allegedly misleading investors, regulators and the public on what it knew about global warming.

Trump's campaign was unavailable for comment.

Trump's preference for secretary of state has jumped around, if reports claiming he was on the verge of appointing ex-Beijing ambassador Jon Huntsman, Giuliani, former U.S. Ambassador to the United Nations John Bolton, Congressman Dana Rohrabacher and Romney are to be believed.