"It is my Great Honour to announce that Senator Marco Rubio, of Florida, is hereby nominated to be The United States Secretary of State," Trump said on Wednesday in a statement, adding that the 53-year-old Cuban American "is a Highly Respected Leader and a very powerful Voice for Freedom".

"Marco will be a strong Advocate for our Nation, a true friend to our Allies, and a fearless Warrior who will never back down from our adversaries. I look forward to working with Marco to Make America, and the World, Safe and Great Again!," Trump added.

In response, Rubio expressed his gratitude and commitment to the role.

"As Secretary of State, I will work every day to carry out his foreign policy agenda. Under the leadership of President Trump, we will deliver peace through strength and always put the interests of Americans and America above all else," Rubio said.

Rubio, whose nomination has been reported by US media outlets for days, reacted quickly to Trump's formal announcement, saying on X that he was "honoured by the trust President Trump has placed in me" to bear the "tremendous responsibility" of leading the Department of State, Xinhua news agency reported.

"As Secretary of State, I will work every day to carry out his foreign policy agenda," he added.

The Secretary of State, as is the case for other cabinet members of the presidential administration, will have to be approved by the Senate before assuming office.

"I look forward to earning the support of my colleagues in the US Senate so the President has his national security and foreign policy team in place when he takes office on January 20," said Rubio, who was elected into the Senate in 2010. He was re-elected in 2022 to serve another six-year term.

Rubio ran an unsuccessful presidential campaign in the 2016 election, which saw Trump win his first presidential term.

Now that Rubio will soon be leaving Capitol Hill, Florida Governor Ron DeSantis is tasked with selecting a replacement for Rubio to serve two of the remaining four years of the Senator's term, until a special election in 2026 to decide who would fill the seat for the last two years.

Many names have been speculated for the position, among them Trump's daughter-in-law Lara Trump, who is now the co-chair of the Republican National Committee.

Trump was rumoured to have been pressing on DeSantis, a presidential candidate vying for nomination against Trump in the 2024 GOP primary, to select his daughter-in-law.

In one scenario, DeSantis, whose potential second run for president is not out of the question, may name his chief of staff, James Uthmeier, to be a placeholder for him in the Senate until his gubernatorial term ends in 2026, at which point DeSantis could run for the seat himself and, if successful, use it as a launching pad for the White House.