US President Donald Trump has escalated his attacks on Attorney-General Jeff Sessions, saying, "I don't have an attorney-general".

Key points: Mr Trump publicly attacks his own Attorney General during interview

Mr Trump publicly attacks his own Attorney General during interview Says he is still angry over Russia investigation and Republican investigations

Says he is still angry over Russia investigation and Republican investigations Later softens his attacks and offers support for Mr Sessions

Mr Trump, in an interview with US political website The Hill released on Wednesday (local time), said that he was "so sad over Jeff Sessions", who he has repeatedly denounced for recusing himself from the Russia investigation.

"He was the first senator that endorsed me. And he wanted to be Attorney-General, and I didn't see it," Mr Trump said in the Oval Office interview.

"And then he went through the nominating process and he did very poorly. I mean, he was mixed up and confused, and people that worked with him for, you know, a long time in the Senate were not nice to him, but he was giving very confusing answers. Answers that should have been easily answered."

The President softened his stance slightly when talking to reporters on the White House lawn hours after the interview's publication, saying, "I'm disappointed in the Attorney-General for numerous reasons, but we have an Attorney-General."

Sorry, this video has expired US President Donald Trump says he's disappointed in Attorney-General Jeff Sessions

Mr Trump has repeatedly asserted that Mr Sessions, a former US senator from Alabama, did not need to step away from the Russia probe, a move the President believes in part led to the appointment of special counsel Robert Mueller, who is investigating contacts between Trump campaign officials and Russians.

Mr Trump suggested that Mr Sessions's rocky senate confirmation hearings may have affected his performance as Attorney-General.

"He gets in and probably because of the experience that he had going through the nominating when somebody asked him the first question about Hillary Clinton or something he said, 'I recuse myself, I recuse myself,'" Mr Trump said.

Department of Justice guidelines recommended the Attorney-General stepped away because of his own contacts with foreign government officials during his time with the 2016 Trump campaign. Mr Sessions told Congress that his decision was not due to any wrongdoing.

President Trump greets the crowd as he arrives for a "Make America Great Again" rally earlier this month. ( Reuters: Kevin Lamarque )

Mr Trump also broadened his attacks beyond the recusal, saying he was unhappy with Mr Sessions's performance on several issues.

"I'm not happy at the border. I'm not happy with numerous things, not just this," Mr Trump said in the interview.

Mr Trump has repeatedly complained publicly and privately about Mr Sessions, pushing him to curtail the Mueller probe, urging him to investigate Ms Clinton and suggesting he should drop investigations into Republican congressmen until after the November midterm elections.

He also said that he does not feel as though Mr Sessions supports him like former attorneys-general Eric Holder and Bobby Kennedy backed presidents Barack Obama and John F Kennedy, respectively.

Mr Trump has repeatedly considered firing Mr Sessions, the nation's top law enforcement officer, only to be opposed by aides who think a dismissal would upend the Russia investigation.

Conservatives who applaud Mr Sessions's hard line stances at the Department of Justice and Republican senators have said they would not confirm a replacement.

But there have been cracks in that blockade of late. South Carolina Senator Lindsey Graham, who once fought for Mr Sessions, recently said that the President was "entitled to having an attorney-general he has faith in" while other Trump allies have suggested that a move could be made after the midterms.

Mr Sessions recently punched back against Mr Trump, saying he and his department "will not be improperly influenced by political considerations".

And Mr Sessions has made clear to associates that he has no intention of leaving his job voluntarily despite Mr Trump's constant criticism.

Mr Trump said in the interview that "we'll see what happens" with Mr Sessions's future.

"We'll see how it goes with Jeff," Mr Trump continued. "I'm very disappointed in Jeff. Very disappointed."

ABC/AP