US President Donald Trump says Attorney-General Jeff Sessions is safe in his job until November but has warned he will "get involved" if the FBI and Justice Department do not "start doing their job".
Trump told Bloomberg News in an interview that Sessions, whom he has repeatedly attacked for recusing himself from oversight of the Russia probe, was safe in his job until the November congressional elections.
But he declined to say if he would keep Sessions on after that.
Speaking later at a campaign rally for Republican Senate candidate Mike Braun in Evansville, Indiana, Trump suggested the leadership of the Justice Department and FBI were biased against Republicans and "people are angry".
"Our Justice Department and our FBI - at the top of each, because inside they have incredible people - but our Justice Department and our FBI have to start doing their job and doing it right and doing it now," Trump said on Thursday.
"I wanted to stay out but at some point if it doesn't straighten out properly ... I will get involved and I'll get in there if I have to."
Trump has previously threatened the Justice Department's traditional independence.
Trump has held Sessions responsible, in part, for the Russia investigation.
After Sessions recused himself, Deputy Attorney-General Rod Rosenstein appointed Special Counsel Robert Mueller to lead the probe into Russia's interference in the 2016 presidential campaign, which Trump has called a "witch hunt".
Asked in the Bloomberg interview whether he would comply if Mueller issued a subpoena for him to appear for questioning, Trump said, "I'll see what happens."
"I view it differently," Bloomberg quoted Trump as saying.
"I view it as an illegal investigation" because "great scholars" have said that "there should never have been a special counsel".
The president resumed his attacks on Session via Twitter last week, saying the attorney-general had never fully exerted control over the Justice Department.
Sessions, in a rare rebuttal, said he took control of the department the day he became attorney-general and would not allow it to be "improperly influenced by political considerations".
Some Republican lawmakers have predicted Trump would replace Sessions, a former US senator, after the November 6 elections.