President-elect Donald Trump announced Tuesday that he intends to nominate ExxonMobil CEO Rex Tillerson for secretary of State, setting up what could be a contentious confirmation process amid bipartisan concerns about the oil titan's Russia ties.

Trump, in a statement, described Tillerson’s career as “the embodiment of the American dream” -- and called him “one of the truly great business leaders of the world” in a tweet.

Tillerson impressed Trump during the two meetings they had in the lead-up to the announcement. Trump called him a “world-class player” during an interview on “Fox News Sunday,” and on Tuesday said he values Tillerson’s “vast experience at dealing successfully with all types of foreign governments.”

Trump has pointed to Tillerson’s relations with Moscow and other political hot spots as a selling point. As ExxonMobil’s chief, he maintained close ties with Russia and was awarded by Russian President Vladimir Putin with the Order of Friendship in 2013, a high honor for a foreign citizen.

However, his ties to Russia haven’t sat well with some in Congress.

Leading Republicans already have expressed reservations about Tillerson, as they contend with intelligence assessments saying Russia meddled in the U.S. presidential election to help Trump – assessments Trump disputes.

Sen. Marco Rubio, R-Fla., a member of the Foreign Relations Committee, tweeted strong, if thinly veiled, criticism of Tillerson on Sunday. He said: “Being a ‘friend of Vladimir’ is not an attribute I am hoping for from a #SecretaryOfState.”

Rubio reiterated those concerns Tuesday, while saying he looks forward to learning more about Tillerson’s background and will ensure he receives a “full and fair but also thorough hearing.”

“While Rex Tillerson is a respected businessman, I have serious concerns about his nomination,” Rubio said in a statement. “The next secretary of state must be someone who views the world with moral clarity, is free of potential conflicts of interest, has a clear sense of America's interests, and will be a forceful advocate for America's foreign policy goals to the president, within the administration, and on the world stage.”

Sen. John McCain, R-Ariz., also has raised concerns – as have environmentalist groups.

But other Republicans, including those considered along with Tillerson for the State Department post, praised his qualifications for the job on Tuesday.

Sen. Bob Corker, chairman of the Senate Foreign Relations Committee that will hold confirmation hearings in January, called Tillerson "a very impressive individual" with "an extraordinary working knowledge of the world." Corker, who had been considered for the secretary of state job, said Trump called him Monday to inform him of the pick.

The 64-year-old Tillerson began his career at Exxon in 1975 as an engineer, rising through the ranks and becoming president and director in 2004 and CEO two years later. He was born in Wichita Falls, Texas, and studied civil engineering at University of Texas.

House Majority Leader Kevin McCarthy, R-Calif., told Fox News’ “Sunday Morning Futures” that Tillerson would be a “smart pick.”

Speaking on ABC News’ “This Week,” incoming Trump chief of staff Reince Priebus also defended Tillerson as an “incredible businessman and American patriot.”

He said “the fact that he actually has a relationship with people like Vladimir Putin and others across the globe is something that [we] shouldn't be ... embarrassed by.”

Asked about tough questions from Republican senators, he said, “We don't have concerns about confirmation.”

Should he be confirmed as America's top diplomat, he will have a pay cut and complicated financial situation to sort out. Tillerson reportedly makes more than $40 million per year and owns more than $100 million of stock in a company that has holdings and dealings throughout the world.

The Associated Press contributed to this report.