Washington DC - Attorney General Merrick Garland announced the appointment of a special counsel to oversee two federal probes into former president Donald Trump.

One investigation will look into Trump's mishandling of classified documents after leaving the White House, while the other will look into his involvement with the January 6 riots at the Capitol building, according to CNN.

On Friday, Garland signed a letter officially appointing Jack Smith to oversee the investigations, requesting he begin serving "immediately."

Smith is a former federal prosecutor and the former chief of the Department of Justice's Public Integrity Section.

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The probes aim to gather more information in both matters, which are already both deeply entrenched in investigations, and call witnesses before a federal grand jury. Subpoenas have already been issued by prosecutors within the past few days.

The move was expected if Trump were to announce his run for a second term as US president in 2024, which he confirmed earlier this week.

Garland noted in his letter that Trump running in 2024 against president Joe Biden, who appointed Garland to his position at the Department of Justice, created "extraordinary circumstances" which justified his choice to appoint the counsel.

Trump is facing multiple criminal investigations, but has argued on multiple occasions that his opponents have "weaponized" the justice system to attack him.