In a series of tweets citing Republican Rep. Trey Gowdy, Trump unleashed yet another attack on Sessions, who, as a senator, was one of the first mainstream Republicans to publicly endorse the real estate magnate's candidacy for president.
Gowdy made the comments about Sessions on Wednesday's edition of "CBS This Morning."
Once friendly with the attorney general, Trump has targeted much of his wrath over the Russia probe at the former Alabama senator after Sessions recused himself last year from the Justice Department's probe into Russian meddling in the 2016 election.
Rudy Giuliani, one of Trump's attorneys in the Russia probe, told CNBC that Trump still seems frustrated over Sessions for the recusal "because he believes he should not have in the first place."
The Justice Department declined to comment.
Sessions' recusal came March 2, 2017, after The Washington Post reported on previously undisclosed contacts between the Alabama Republican and the Russian ambassador during the campaign and the transition period. Sessions, who was a key surrogate and advisor for Trump during the campaign, had not disclosed the meetings during his confirmation hearing before the Senate.
The Wednesday tweets came on the heels of a New York Times article that said the president had asked Sessions to reverse his decision to recuse himself.
Special counsel Robert Mueller is investigating the reported request as part of an inquiry into whether Trump obstructed justice.
Trump has repeatedly denied that his campaign colluded with the Kremlin to undermine Democrat Hillary Clinton's candidacy. He also has denied that he obstructed justice, and has often called the probe a "witch hunt."
A representative for the the White House did not immediately respond to CNBC's request for comment.
CNBC's Brian Schwartz contributed to this article.