US President Donald Trump's administration has fired more than a dozen justice department lawyers who worked on two criminal cases against him.

They were fired after Acting Attorney General James McHenry concluded they could not "be trusted to faithfully implement the president's agenda because of their significant role in prosecuting the president", a department official told the BBC's US partner CBS News.

The lawyers were part of former special counsel Jack Smith's team which investigated Trump's alleged mishandling of classified documents and his alleged attempt to overturn his 2020 election defeat.

The firings on Monday are effective immediately.

Mr Smith was appointed as special counsel in 2022 to oversee the two justice department cases into Trump. The president had vowed to fire him "within two seconds" of taking office, but he quit before his inauguration.

Both cases resulted in criminal charges against Trump, who pleaded not guilty.

But the cases were closed following his November election win. Prosecutors wrote that justice department regulations do not allow the prosecution of a sitting president.

It was not immediately clear which members of Mr Smith's team were fired.

Many of those who worked on Mr Smith's teams were career corruption and national security prosecutors who had worked across various administrations and were appointed to the cases.

They reportedly received a letter on Monday which said their role in investigating and prosecuting the president made them unsuitable to work in the department.

"Firing prosecutors because of cases they were assigned to work on is just unacceptable," former US Attorney Joyce Vance told NBC News. "It's anti-rule of law; it's anti-democracy."

The firings follow a major reassignment of some of the justice department's top officials with expertise in a wide range of fields including national security and public corruption. On Monday, one of them, the chief of the public integrity section, reportedly resigned.

Trump and his team have accused the justice department of pursuing politically motivated cases against him, his associates and Republicans. Trump vowed an immediate overhaul of the department, which he says has been "weaponised" against him, while campaigning for re-election.

His nominee to lead the justice department, Pam Bondi, has echoed Trump's view that federal prosecutions against him were political persecution, saying the department "had been weaponised for years and years and years".

Mr Smith has publicly defended his work. In a letter accompanying the final draft of his report into Trump's actions after the 2020 election, he wrote: "The claim from [Trump] that my decisions as a prosecutor were influenced or directed by the Biden administration or other political actors is, in a word, laughable."

Also on Monday, Washington DC's top federal prosecutor announced the launch of an internal review into the charging decisions behind hundreds of Capitol riot cases, according to CBS.

Acting US Attorney Edward Martin, a Trump appointee, ordered prosecutors in his office to turn in documents, emails and other information related to the previous administration's decision to bring an obstruction charge against more than 200 Capitol attack defendants.