WASHINGTON — President Donald Trump announced Friday that he plans to nominate William Barr for attorney general, and confirmed that former Fox News anchor Heather Nauert is his pick to replace Nikki Haley as U.N. ambassador.

"He was my first choice from Day 1," Trump said of Barr, calling him a "highly respected lawyer" and "one of the most respected jurists in the country."

If confirmed by the Senate, it would be Barr's second stint as head of the Justice Department. He served as attorney general from 1991 to 1993 under President George H.W. Bush.

"Hopefully that process will go very quickly," Trump said of Senate confirmation. "I think he will serve with great distinction."

Barr may face tough questions in the Senate. Multiple Democrats on the Senate Judiciary Committee have already cited concerns about Barr, stemming from his previous statements on topics such as the Hillary Clinton email investigation and James Comey's firing as FBI director.

Sen. Mazie Hirono, D-Hawaii, told CNN on Friday that she "would have a hard time" backing Barr, saying he had "auditioned for the job by catching President Trump's attention by talking about how Hillary Clinton should continue to be investigated."

In October 2016, Barr wrote an op-ed in The Washington Post praising Comey for reopening the investigation into Clinton's use of a private email server shortly before the presidential election.

After Comey's firing in May 2017, Barr wrote another Post op-ed, defending Trump's decision.

Barr would succeed Jeff Sessions, who resigned as attorney general under pressure in November.

After Sessions' ouster, Trump appointed Matthew Whitaker as acting attorney general. Almost immediately, Whitaker came under fire for previous comments against special counsel Robert Mueller's investigation.

Barr may face similar criticism. Sen. Richard Blumenthal, D-Conn., released a statement shortly after Trump's announcement, saying he will demand that Barr commit to protecting the Mueller investigation.

"The Senate must closely scrutinize this nominee, particularly in light of past comments suggesting Mr. Barr was more interested in currying favor with President Trump than objectively and thoughtfully analyzing law and facts," Blumenthal said in the statement.

Sen. Lindsey Graham, R-S.C., who is expected to be the next chairman of the Senate Judiciary Committee, pledged full support for Barr in a statement Friday.

"I will do everything in my power to push him through the Senate Judiciary Committee and onto the floor of the Senate for eventual confirmation as soon as possible," Graham said.

Trump's choice of Nauert to replace Haley, which he also confirmed Friday at the White House, had been previously reported by NBC News.

"She's very talented, very smart, very quick, and I think she's going to be respected by all," Trump said of Nauert.

The former “Fox & Friends” anchor has been spokeswoman for the State Department since April 2017.

The president also teased a third personnel decision to be announced Saturday as he attends the Army-Navy game in Philadelphia.

"I can give you a little hint — it will have to do with the Joint Chiefs of Staff and succession," Trump said.