WASHINGTON - The US Senate on Monday unanimously confirmed Marco Rubio as secretary of state.

The 99-0 vote was the first by senators to confirm US President Donald Trump's cabinet nominees. And it could be the final time Rubio, a senator representing the state of Florida since 2011, casts a vote in the Senate.

An avid follower of Trump and a loyal advocate of his policies, Rubio thanked Trump for "his confidence" at his confirmation hearing on Wednesday. He pledged that, if confirmed, he would make keeping Trump's foreign policy promise "the core mission" of the US Department of State.

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After the vote, Rubio told reporters that he expects himself to be "sworn in tomorrow morning".

Rubio, 53, is a descendant of Cuban immigrants.