Exxon Mobil's top brass said the company was in the early stages of front-office changes now that Rex Tillerson is tapped as the next U.S. secretary of state.

The board of directors at Exxon said it congratulated chairman and CEO Tillerson for his nomination as the top U.S. diplomat in the administration of Donald Trump.

"The board will be meeting shortly regarding transition," the company said in a statement.

Tillerson joins a long list of business and political leaders with strong energy ties asked to join the incoming administration. Trump in a statement said Tillerson's leadership at Exxon, one of the largest oil and gas companies in the world, qualified him for the post of secretary of state.

"His tenacity, broad experience and deep understanding of geopolitics make him an excellent choice for secretary of state," Trump said.

Exxon reported third quarter net income of $2.65 billion, against $4.24 billion during the same period last year. Production was down 3 percent to 3.8 million barrels of oil equivalent per day.

It was the fourth consecutive quarter of a downturn for the world's largest publicly traded oil company. First quarter earnings of $1.8 billion were the weakest in more than a decade.

Sen. John McCain, an Arizona Republican, has been a vocal critic of the incoming administration, pointing to ties between Trump's team and Russia. Intelligence allegations raised in the wake of the election suggest Russia may have interfered in Trump's favor.

Speaking with National Public Radio, McCain said he was concerned about the relationship between Trump, Tillerson and Russian President Vladimir Putin, referred to by the Arizona senator as "a butcher."

Tillerson's company has done business with Russian oil companies that have been the target of U.S. sanctions.

Tillerson, who has no political experience, said in a statement the United States must work to strengthen its alliances by restoring the credibility of U.S. foreign relations. His appointment was praised by Condoleezza Rice, a security advisor to former President George W. Bush, and Dick Cheney's, the vice president under Bush. Both Rice and Cheney had strong ties to the energy sector.

McCain told NPR he'd wait for the confirmation process.

"I am not making a judgment about Mr. Tillerson," he said. "That's why we have hearings, advise and consent and I will withhold judgment."

Assuming unity among Democrats in the Senate, only a few Republican defectors would be needed to shoot down a Cabinet pick next year.