Sessions, a longtime USA senator and early supporter of Trump's presidential bid, drew Trump's ire when he recused himself in March 2017 from issues involving the 2016 White House race.
Later on, he said: "Open up the papers & documents without redaction?"
"We have somebody who they seem to go after a lot of Republicans, " Trump said of Sessions in an interview with Fox News that aired Thursday, adding that the inability of his attorney general to "control" his department was "a regrettable thing".
Sessions issued a rare statement on Thursday, seemingly rebuking Trump directly and pledging to remain untainted by political bias in his work at the agency.
Former U.S. attorney Joseph diGenova charged President Trump has never had a "fully engaged" attorney general.
While President Trump urges his top law enforcement official to go after his political enemies... the president AGAIN taking a swipe at the Attorney General - tweeting Saturday, "Jeff Sessions said he wouldn't allow politics to influence him only because he doesn't understand what is happening underneath his command position".
Mueller took over the FBI's investigation into the Russian attack on the 2016 election and whether Americans were involved, including people on the Trump campaign. Strzok, who was removed from special counsel Robert Mueller's investigation in the summer once the texts were brought to his attention, was sacked by the FBI this month. Trump said this was "small potatoes" compared to Hillary Clinton.
During the interview, Trump didn't directly answer whether he planned to fire Sessions or deputy attorney general Rod Rosenstein, who oversees the Russian Federation investigation.
"But when everybody sees what's going on in the Justice Department - I always put "justice" now with quotes - it's a very, very sad day". I said, what kind of a man is this?
Trump's anger with Sessions boiled over in the Fox interview, in which the president also expressed frustration with the plea agreement his onetime legal "fixer" Michael Cohen cut with prosecutors, including implicating Trump in a crime that Cohen admitted.
- Donald J. Trump (@realDonaldTrump) August 25, 2018.@LindseyGrahamSC "Every President deserves an Attorney General they have confidence in".
Trump reprised a litany of complaints about the Justice Department and the Federal Bureau of Investigation, attacking both without providing evidence they had treated him and his supporters unfairly. When asked, Trump didn't dismiss the notion of firing the attorney general.
The Republicans have argued throughout the investigation that they are confident Trump would not try to interfere with it, and thus, they said, legislation protecting Mueller was unnecessary.
"So unfair Jeff, Double Standard", Trump tweeted. His statement came moments before he was set to arrive at the White House for a meeting on criminal justice reform.