Trump's top team: who's who?

US President-elect Donald Trump is building his administration team ahead of retaking the White House in January, handing top roles to his closest allies.

While many of his cabinet nominations require approval by the Senate, Trump is trying to bypass that oversight by forcing through so-called recess appointments.

Here are the key people nominated by Trump for positions in his incoming administration:

Billionaire Elon Musk has been named to lead a new "Department of Government Efficiency," targeting $2 trillion in cuts from the federal government's $7 trillion budget, according to the businessman -- although no one has explained how such drastic cuts would be made.

The world's richest man has pledged to bring his "hardcore" management style to Washington while promising "fair and humane" transitions for sacked federal workers.

Trump said that another wealthy ally, Vivek Ramaswamy, would co-lead the new department.

Fox News host and US Army veteran Pete Hegseth was nominated to be the next defence secretary, tasked with leading the world's most powerful military.

Hegseth joined Fox News in 2014 and is a host on Fox and Friends Weekend and Fox Nation. He has also authored several books.

Trump has said that "with Pete at the helm, America's enemies are on notice."

Longtime Trump loyalist and South Dakota Governor Kristi Noem was selected to head the Department of Homeland Security, a key role in any Trump plan to restrict immigration or deport undocumented migrants en masse as he has promised.

In her memoir, Noem recounted having shot dead an "untrainable" pet dog after a hunting excursion gone awry. The 52-year-old has said her action showed she was able to make tough choices.

New York congresswoman Elise Stefanik, a fierce Trump ally and pro-Israel stalwart, was Trump's pick for US ambassador to the United Nations.

Stefanik will represent the administration at the UN as the world body grapples with the war in Ukraine as well as Israel's bombardments of Gaza and Lebanon.

Congressman and former special forces officer Mike Waltz has been named by Trump to be his national security advisor, tasked with handling foreign policy challenges including the wars in Ukraine, Gaza and Lebanon.

Waltz is critical of both China, which he has said is an "existential" threat to the United States and of Russia -- while arguing that Washington should cease supporting Ukraine's war effort in favour of Trump's so-far vague promise of a negotiated settlement.

Trump has called on former Arkansas governor Mike Huckabee to be US ambassador to Israel, where he has travelled several times over the years.

Trump has said the Christian pastor-turned-politician "loves Israel, and the people of Israel, and likewise, the people of Israel love him."

In 2017, Huckabee was present in Maale Adumim for the expansion of one of Israel's largest settlements in the occupied West Bank.

"There's no such thing as a settlement; they're communities, they're neighbourhoods, they're cities. There's no such thing as an occupation," he told CNN at the time.

Lee Zeldin has been selected to head the Environmental Protection Agency, with a mandate to slash climate and pollution regulations.

Veteran immigration official Tom Homan will be the country's "border czar", with Trump saying Homan would be in charge of "all Deportation of Illegal Aliens back to their Country of Origin."

Susie Wiles, Trump's election campaign chief, has been named as his chief of staff.

Trump also announced he was choosing his former director of national intelligence John Ratcliffe to lead the Central Intelligence Agency.

- Secretary of State: Marco Rubio -

Multiple US media have said Trump is expected to tap Senator Marco Rubio to be his secretary of state, setting the stage for an existential battle against China.

Rubio has said China "doesn't just seek to be the most powerful nation in the world, they seek to reorient the world."

He is also a fervent supporter of Israel and a longtime critic of Russian President Vladimir Putin.

Billionaire hedge fund manager Scott Bessent, a key donor and advisor, is viewed as the top candidate for treasury secretary, in charge of pushing through Trump's agenda of low taxes, less regulation and high tariffs.