President Donald Trump has said he is naming Fox News host Jeanine Pirro, a former county prosecutor and elected judge, to be the top federal prosecutor for the nation's capital after abandoning his first pick for the job.

Pirro, who joined Fox News in 2006, co-hosts the network's show "The Five" on weekday evenings. She was elected as a judge in New York's Westchester County Court in 1990 before serving three terms as the county's elected district attorney.

Trump tapped Pirro to at least temporarily lead the nation's largest US Attorney's office after pulling his nomination of conservative activist Ed Martin Jr. for the position earlier on Thursday. In a post on Truth Social, Trump said he was naming Pirro as the interim US attorney in Washington D.C., but didn't indicate whether he would nominate her for the Senate-confirmed position on a more permanent basis.

"Jeanine is incredibly well qualified for this position, and is considered one of the Top District Attorneys in the History of the State of New York. She is in a class by herself," Trump wrote.

Trump withdrew Martin from consideration after a key Republican senator said he could not support Martin for the job due to his defense of rioters who stormed the Capitol on January 6, 2021.

"He's a terrific person, and he wasn't getting the support from people that I thought," Trump told reporters in the Oval Office on Thursday. He later added: "But we have somebody else that will be great."

Pirro is the latest in a string of Trump appointments coming from Fox News — a list that includes Defence Secretary Pete Hegseth, who co-hosted "Fox & Friends Weekend."

Martin has served as acting US Attorney for the District of Columbia since Trump's first week in office. But his hopes of keeping the job faded amid questions about his qualifications and background. Martin had never served as a prosecutor or tried a case before taking office in January.

Martin has stirred up a chorus of critics during his brief but tumultuous tenure in office. He fired and demoted subordinates who worked on politically sensitive cases. He posted on social media about potential targets of investigations. And he forced the chief of the office's criminal division to resign after directing her to scrutinise the awarding of a government contract during Democratic President Joe Biden's administration.

Martin's temporary appointment is due to expire on May 20.

Pirro, a 1975 graduate of Albany Law School, has significantly more courtroom experience than Martin. She led one of the nation's first domestic violence units in a prosecutor's office.

After her elected terms as a judge and district attorney, Pirro briefly campaigned in 2005 as a Republican to unseat then-Democratic Sen. Hillary Rodham Clinton before announcing that she would run for New York attorney general instead. She lost that race to Andrew Cuomo, son of former New York Gov. Mario Cuomo.

Pirro became an ubiquitous television pundit during O J Simpson's murder trial, often appearing on CNN's "Larry King Live". During her time on Fox News, she has frequently interviewed Trump.

In the final minutes of his first term as president, Trump issued a pardon to Pirro's ex-husband, Albert Pirro, who was convicted in 2000 on conspiracy and tax evasion charges.

In 2021, voting technology company Smartmatic USA sued Fox News, Pirro and others for spreading false claims that the company helped "steal" the 2020 presidential election from Trump. The company's libel suit, filed in a New York state court, sought USD 2.7 billion from the defendants.