President Donald Trump announced Wednesday that Jeff Sessions resigned as US attorney general at the request of the White House.
"We are pleased to announce that Matthew G. Whitaker, Chief of Staff to Attorney General Jeff Sessions at the Department of Justice, will become our new Acting Attorney General of the United States. He will serve our Country well," the president tweeted.
"We thank Attorney General Jeff Sessions for his service, and wish him well! A permanent replacement will be nominated at a later date," Trump added.
The former Alabama senator presented his resignation in a letter sent to the president, which was released on Wednesday but lacks a date.
"At your request I am submitting my resignation," Sessions wrote in the letter.
Sessions thanked the staff at the Department of Justice for their work, but refrained from making any criticism against the president.
The relationship between the president and Sessions has been tense for more than a year, largely as a result of the attorney general's decision to recuse himself from the investigation into alleged Russian meddling in the 2016 presidential election because of his own involvement in the Trump campaign.
This preceded the appointment of special counsel Robert Mueller to investigate alleged coordination between the Kremlin and the Trump campaign.
In August, Trump again blasted Sessions for having recused himself from the Russia probe.
The president has repeatedly criticized Sessions for his decision, which led the No. 2 at the Department of Justice, Rod Rosenstein, to take control of the Russia probe and appoint Mueller.
The president's attacks against Mueller have created concern among the opposition, as well as among some Republicans, for fear that he will fire the special counsel.