President Donald Trump said Friday that he will nominate Heather Nauert, the State Department spokeswoman and former Fox host, to replace Nikki Haley as the US ambassador to the UN.

Nauert, 48, did not have experience in foreign policy, government, or politics when she left her job at Fox to join the Trump administration last year.

Trump also announced Friday that he'll nominate former Attorney General William Barr to replace outgoing Justice Department chief Jeff Sessions.

President Donald Trump told reporters on Friday that he'll nominate Heather Nauert, the State Department spokeswoman and one of the country's highest-ranking diplomats, to replace Nikki Haley as the US ambassador to the UN.

Trump also announced on Friday that he'll nominate William Barr, who served as attorney general under President George H.W. Bush for three years, to replace Jeff Sessions as attorney general.

Barr, a respected Republican attorney, has made some critical public comments about special counsel Robert Mueller's investigation into ties between the Trump administration and Russia, including suggesting that Mueller's team may be politically biased against the president.

Both Barr and Nauert will likely face tough confirmation hearings.

Haley abruptly resigned in October — a move she said she had discussed with Trump for months — and is set to leave by the end of the year.

Nauert, 48, has for months balanced two high-profile positions at the State Department after Trump picked her to be acting undersecretary for public affairs and public diplomacy. And while Nauert is generally well-liked by her colleagues, many say she lacks the necessary experience for her jobs and is overloaded with responsibility.

There has never before been a State Department spokesperson who has simultaneously served in that undersecretary role, a top-ranking post that directs strategic messaging, promotes cross-cultural exchanges, and oversees the Global Engagement Center, which fights foreign propaganda.

Read more: How Heather Nauert's unlikely rise at the State Department has made her a top contender for White House press secretary

And unlike most of her predecessors in both roles, Nauert, a former Fox News host, arrived in Washington last year without experience in foreign policy, government or politics.

Reports had also surfaced in recent months that Nauert was high on the administration's list of potential replacements for the White House press secretary Sarah Huckabee Sanders, who is said to be considering leaving around the end of the year. Sanders has publicly denied reports that she plans to leave.