US Attorney General Jeff Sessions' allies say President Donald Trump is carrying out a deliberate public campaign to pressure him to quit, rather than fire him outright, but America's top lawyer has no intention of resigning.
On Monday, Mr Trump had called his attorney general "beleaguered".
In the latest attack, the president said in a tweet on Tuesday that Mr Sessions had "taken a VERY weak position" on investigating his former opponent in the 2016 presidential election, Democratic nominee Hillary Clinton, over her use of a private email server.
Attorney General Jeff Sessions has taken a VERY weak position on Hillary Clinton crimes (where are E-mails & DNC server) & Intel leakers!— Donald J. Trump (@realDonaldTrump) July 25, 2017
Mr Trump is angry that Mr Sessions recused himself from the federal investigation into possible collusion between Mr Trump's election campaign team and Russia. The Kremlin says it did not interfere in the election, and Mr Trump has denied any collusion.
Mr Sessions' recusal means he has no oversight of Special Counsel Robert Mueller, whose wide-ranging investigation has focused on Trump aides and the president's son-in-law Jared Kushner.
Speaking later at the White House, Mr Trump repeated his disappointment with Mr Sessions and said he wanted the attorney general to be "much tougher on the leaks from intelligence agencies".
"Rarely have they ever leaked before at a very important level. I told you before I'm very disappointed with the attorney general but we will see what happens. Time will tell."
The president's new communications director, Anthony Scaramucci, agreed in a radio interview that the attorney general's days could be numbered
Two people close to Mr Sessions said the attorney general, who was the first Republican senator to back Mr Trump's presidential campaign, has been deeply offended by the public berating from his boss, but his resolve to stay was strong.
The public attacks by a president on a member of his own cabinet and one-time close political ally have stunned many in Washington.
"In an administration where a lot of unexpected things have happened, this may be the most unexpected. This has risen to a level that we have never seen before," said Douglas Heye, a former top aide to former Republican House Majority Leader Eric Cantor.
Republican MPs sprang to Mr Sessions' defence on Tuesday, and the top Democrat in the Senate, Chuck Schumer, accused Mr Trump of trying to "bully his own attorney general out of office".
Mr Trump's public criticism of Mr Sessions began in earnest in an interview with the New York Times last week in which he said he would not have hired him had he known he would recuse himself from the Russia investigation.
He followed that with the critical tweets, and close aides - White House press secretary Sarah Sanders and newly installed White House communications director Anthony Scaramucci - have gone on television to reinforce Mr Trump's frustration with Mr Sessions.
- Reuters / CNN / Wires