Marco Rubio
Marco RubioReuters

Sen. Marco Rubio announced Monday morning that he would support President Donald Trump's nominee for Secretary of State, removing the last significant stumbling block to the nomination.

"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 statement on his Facebook page.

"Therefore, despite my reservations, I will support Mr. Tillerson’s nomination in committee and in the full Senate."

Rubio had previously grilled Tillerson aggressively during his nomination hearing earlier this month. He and other Senators including other Republicans, expressed concerns over the former Exxon Mobile CEO's alleged connections with foreign governments, including with the government of Russia.

Rubio had been the lone Republican holdout on the Senate Foreign Relations Committee. Had he opposed Tillerson's nomination, the makeup of the committee would have denied Tillerson the majority and could have held up the confirmation process indefinately.

Earlier, Senators John McCain and Lindsay Graham, two Republican Senators who had also expressed misgivings about Tillerson's nomination, announced their intentions to vote to approve his appointment.