He said he wanted Sessions "to be much tougher on leaks in the intelligence agencies that are leaking like they never have before. . . . You can't let that happen.''
It is unheard of for a Cabinet-level official to be subjected to such visceral and public criticism, which has now gone on for a week.
But Sessions showed no sign of buckling today, and in fact his position was bolstered by support from prominent conservatives taking his side in the fight with Trump.
In a recent conversation, Sessions's chief of staff, Jody Hunt, told White House Chief of Staff Reince Priebus that the Attorney-General had no intention of stepping down.
Hunt, according to people familiar with the conversation, made it clear to Priebus that Sessions "plans to move forward with his agenda in the department and he has no plans for resigning,'' according to one person familiar with the exchange. Priebus, for his part, did not say Trump planned to fire Sessions if he did not leave, these people said.
Trump's reluctance to act on his anger and fire Sessions may be based in part on the lack of an immediate plan for a successor at the Justice Department.
While Trump has discussed potential candidates to replace Sessions, senior White House officials have not settled on someone, and may not anytime soon, Administration officials said. If Sessions were to be fired without even a temporary replacement lined up, the deputy Attorney-General who oversees the Russia probe, Rod Rosenstein, would assume authority over the entire Justice Department.
One Republican close to the White House said a number of senior aides, including newly hired communications director Anthony Scaramucci, have urged Trump to sit down with Sessions and work through their differences. So far, there has been little enthusiasm for that suggestion, the Republican said.
One informal adviser to the Trump White House said there is another reason Trump has yet to fire Sessions: "The President doesn't want to be seen as firing another law enforcement official''.
After Trump fired Comey, one unintended consequence was the appointment of Robert Mueller as special counsel overseeing the Russia probe.
Earlier today, Trump had tweeted that Sessions was "very weak'' on investigating Hillary Clinton's "crimes'' and had not aggressively hunted those who have leaked intelligence secrets since he has been in office.
The President's insistence that Clinton be investigated runs contrary to his own past statements, and the decision by the Justice Department and the FBI last year to close the investigation into her use of a private email server when she was Secretary of State. Sessions has recused himself from Clinton-related matters, citing his involvement with the presidential campaign as one of Trump's major advisers.
The public humiliation of Sessions at the hands of the President he helped get elected was galling to many conservatives, who see Sessions as the Cabinet official who has most assiduously pursued Trump's policy goals, from cracking down on illegal immigration to targeting street gangs.
Republicans publicly rallied to Sessions' defence. Senator Orrin Hatch said Sessions "is among the most honourable men in government today. . . . I have full confidence in Jeff's ability to perform the duties of his office and, above all, uphold the rule of law.''
And Breitbart, the conservative website, posted an article saying the President's public attack on Sessions "only serves to highlight Trump's own hypocrisy" and it warned that the President's stance could "fuel concerns from his base [which sees] Sessions as the best hope to fulfill Trump's immigration policies.''
Even among Democrats, Trump's treatment of Sessions raised concerns. Senator Dianne Feinstein the ranking Democrat of the Senate Judiciary Committee, said, "What's happening is just terrible. The Attorney-General did the right thing. The Attorney-General was nothing but loyal to Donald Trump. He took an oath of office to represent the Constitution, the law and the people.''
Current and former Justice Department officials said they hope Sessions holds out, refusing to resign as a means of defending the department's independence.
One former Justice Department official said the President's anger seems to stem from a misunderstanding about how the department actually works. The White House, he said, should not be interfering with criminal investigations.
"For those of us that want this Administration to succeed, this is incredibly self-destructive behaviour,'' the official said.
Justice Department employees said the President's comments are damaging the reputation and morale of the department.
"It's just insanity,'' said one employee. Another official said there was still hope in the building that Sessions could survive, and that Trump's fury might abate. "This might be the one instance where everyone else just kind of rolls their eyes and moves on,'' the official said.
The surge of support for Sessions is remarkable, considering how isolated he has been within the government. Sessions is viewed warily by many at the FBI for his role in Comey's firing, and he is increasingly distant from the White House, despite the fact that some of his former Senate staffers serve there.
Administration officials said the President and his staff are also upset that Sessions held a news conference last week, in which he said he planned to remain on the job. Some in the White House saw that statement as unnecessarily antagonising the President.
"Can you imagine any other president having to go this far to tell someone you need to go?'' said a person informally advising the White House. "When Sessions said he wouldn't resign, it's like poking fire. You know who you're dealing with."
Yet within the Justice Department, that reaction was viewed as another indication of how little White House officials appear to understand what the Justice Department does. The news conference had been scheduled a week earlier based on an arrest overseas, and a senior European law enforcement official had flown in to participate.
Cancelling the news conference, Justice Department officials reasoned at the time, would be a bigger problem than going forward. Sessions tried to keep his answers low-key, they added.
