Donald Trump has selected US senator Marco Rubio to be his secretary of state, the New York Times reports, putting the Florida-born politician on track to be the first Latino to serve as America's top diplomat.
Rubio was arguably the most hawkish option on Trump's shortlist for secretary of state, and he has in years past advocated for a muscular foreign policy with respect to America's geopolitical foes, including China, Iran and Cuba.
Earlier the US-president elect picked Mike Waltz to be his national security adviser, two sources familiar with the matter told Reuters, tapping a retired Army Green Beret who has been a leading critic of China.
Over the last several years Rubio has softened some of his stances to align more closely with Trump's views.
The new administration will confront a world more volatile and dangerous than it was when Trump took office in 2017, with wars raging in Ukraine and the Middle East and China aligning itself more closely with US foes Russia and Iran.
The Ukraine crisis will be high on Rubio's agenda.
Rubio, 53, has said in recent interviews that Ukraine needs to seek a negotiated settlement with Russia rather than focus on regaining all territory that Russia has taken in the last decade. He was also one of 15 Republican senators to vote against a $US95 billion military aid package for Ukraine, passed in April.
Waltz has criticised Chinese activity in the Asia-Pacific and voiced the need for the United States to be ready for a potential conflict in the region.
The national security adviser is a powerful role, which does not require Senate confirmation. Waltz will be responsible for briefing Trump on key national security issues and co-ordinating with different agencies.
Waltz has publicly praised Trump's foreign policy views.
"Disruptors are often not nice ... frankly our national security establishment and certainly a lot of people that are dug into bad old habits in the Pentagon need that disruption," Waltz said during an event earlier this year.
"Donald Trump is that disruptor."
Waltz has a long history in Washington's political circles.
He was a defence policy director for defence secretaries Donald Rumsfeld and Robert Gates and was elected to Congress in 2018. He is the chairman of the House Armed Services subcommittee overseeing military logistics and also on the select committee on intelligence.
Earlier Elise Stefanik was appointed as United States ambassador to the United Nations.
"I am honoured to nominate chairwoman Elise Stefanik to serve in my cabinet as US ambassador to the United Nations. Elise is an incredibly strong, tough, and smart America First fighter," Trump said.
Stefanik, 40, a New York representative and House Republican Conference chair, has been a fierce Trump ally.
Trump also announced the appointment of Republican former Congressman Lee Zeldin, who often voted against legislation on green issues including a measure to stop oil companies from price gouging, to head the Environmental Protection Agency.
Trump has said he plans to begin rescinding EPA and Transportation Department vehicle pollution rules on his first day in office and is considering paring back or eliminating EV tax breaks and other incentives.
Trump also plans to rescind California's ability to set its own vehicle emissions rules, as he did in 2019.
"We will restore US energy dominance, revitalise our auto industry to bring back American jobs, and make the US the global leader of AI," Zeldin said on the X social media platform.
Zeldin will have to be approved by the Senate, which regained a Republican majority at the US election.
