WASHINGTON: President-elect Donald Trump will reportedly name ExxonMobil chief Rex Tillerson, an oilman with deep ties to Russia, as secretary of state Tuesday despite mounting support for a congressional probe into Moscow's alleged interference in the US election.

"I will be making my announcement on the next Secretary of State tomorrow morning," Trump said late Monday using his favored medium, Twitter.

News outlets including The New York Times, Washington Post and NBC News cited sources as saying the real estate mogul had settled on Tillerson after a drawn-out and public search for the nation's top diplomat.

The president-elect also said late Monday that his businesses would steer clear of negotiating new deals during his White House tenure.

"No new deals will be done during my term(s) in office," the 70-year-old tycoon said on Twitter, adding that he would be leaving his businesses before taking office and that his two adult sons, Don and Eric, would manage his companies.

Critics argue that it would be an unprecedented ethical conflict for Trump to maintain interest in properties spanning the globe -- investments that rely partly on goodwill from foreign governments and regulators.

- Close ties with Russia -

Once in office, Trump's secretary of state will be tasked with overseeing international relations for a political novice who seems intent on trashing protocol and upending relationships built on decades of delicate diplomacy.

If he is indeed nominated on Tuesday, Tillerson -- who has no formal foreign policy background -- is sure to face sharp questions in Senate confirmation hearings.

As ExxonMobil's president and CEO, the 64-year-old Texan oversees the company's business activities in more than 50 countries.

He has opposed sanctions on Russia and in 2013 was awarded Russia's Order of Friendship by President Vladimir Putin following several years of Exxon projects in the country.

On Monday, leading senators gave their backing to a congressional investigation into US intelligence assessments that Russia interfered in the election, putting top Republicans on a collision course with the incoming president.

The president-elect has dismissed the intelligence reports about Russian interference as "ridiculous," defying an increasing number of senators from his own party, as well as top Democrats, the Central Intelligence Agency and the outgoing White House.

US media have reported for days on secret CIA findings that Moscow sought to bolster Trump's election bid, against Democratic former secretary of state Hillary Clinton, by releasing hacked Democratic Party documents.

If Tillerson is nominated, he will have bested eight or nine contenders for the job, including former CIA director David Petraeus, former UN ambassador John Bolton and Senate Foreign Relations Chairman Bob Corker.

Also on that list was erstwhile Trump critic and former Massachusetts governor Mitt Romney, who indicated on Facebook he was out of the running shortly after Trump said he would soon make his choice official.

"It was an honor to have been considered for secretary of state of our great country," Romney wrote.

"My discussions with President-elect Trump have been both enjoyable and enlightening. I have very high hopes that the new administration will lead the nation to greater strength, prosperity and peace."

CNN reported that Trump had called Romney to tell him he had not been selected.

- Ruffling feathers -

With more than five weeks to go before he is sworn in, Trump is already ruffling feathers with his statements about two major world powers: Russia and China.

The president-elect has stoked alarm -- even among fellow Republicans -- by calling for closer ties with Moscow, in contrast to received wisdom in Washington that Russia remains a global security threat.

He has dismissed as "ridiculous" reports that US intelligence has concluded that Russia interfered in last month's presidential election to sway the vote in his favor.

And Sino-US relations have come under strain after a series of moves by Trump that provoked China, America's biggest single goods trading partner and the holder of almost a trillion dollars in US government debt.

The incoming president has suggested that Beijing may have to make concessions on trade if US policy toward China is to stay the same. He also directly challenged China over its currency and its takeover of disputed islets in the South China Sea.

That came after Trump raised eyebrows by taking a congratulatory call from the president of Taiwan, a self-ruling island that Beijing considers a rogue province awaiting unification.

-AFP