The U.S. Senate voted 56 to 43 to confirm former Exxon Mobil Corp. CEO Rex Tillerson as President Donald Trump's secretary of state.

Three Democrats, Sens. Joe Manchin, D-W.Va., Mark Warner, D-Va., and Heidi Heitkamp, D-N.D., and one independent, Sen. Angus King of Maine, joined Republicans in voting to confirm Tillerson, who needed a 51-vote majority to be confirmed.

Tillerson during his confirmation hearing fielded questions about his ties to Russia, his stance on climate change and whether he considers there to be human rights violations in countries including Saudi Arabia and the Philippines.

Some of the most ardent questioning came from Republican Sen. Marco Rubio of Florida, who at one point asked Tillerson whether he considers Russian President Vladimir Putin a "war criminal." Tillerson replied that he would not use that term.

Rubio later said he would vote to advance Tillerson out of the Senate Committee on Foreign Relations despite "troubling" answers on several questions. "Given the uncertainty that exists both at home and abroad about the direction of our foreign policy, it would be against our national interests to have this confirmation unnecessarily delayed or embroiled in controversy," Rubio said in a Jan. 23 Facebook post.

Trump had lunch with Tillerson earlier in the day Feb. 1, according to the White House. The meeting was closed to the press.