Attorney General William Barr said Monday he does not expect the Justice Department to probe former President Barack Obama or former Vice President Joe Biden as part of its review of the FBI’s investigation into Russian interference in the 2016 election.

Speaking at a news conference to discuss a shooting at a Florida naval base last year, Barr was asked about President Donald Trump’s suggestion that Obama and Biden committed crimes. Saying he was not specifically taking issue with Trump’s remarks, Barr criticized “increasing attempts to use the criminal justice system as a political weapon.”

“The legal tactic has been to gin up allegations of criminality by one’s political opponents based on the flimsiest of legal theories,” Barr said. “This is not good for political life and it’s not good for the criminal justice system. And as long as I’m attorney general, the criminal justice system will not be used for partisan political ends.”

Barr then dismissed the idea that U.S. Attorney John Durham, who is overseeing the review of the FBI probe, would investigate Obama or Biden, though he declined to say who Durham is targeting.

“As to President Obama and Vice President, whatever their level of involvement, based on the information I have today, I don’t expect Mr. Durham’s work will lead to a criminal investigation of either man,” Barr said. “Our concern over potential criminality is focused on others.”

As he has noted previously, Barr said a Justice Department investigation of either Trump or Biden, the assumed Democratic presidential nominee, would have to be approved by the attorney general.

“We live in a very divided country right now and I think it’s critical that we have an election where the American people are allowed to make the choice between President Trump or Biden based on robust debate of policy issues,” he said. “Can’t allow this to be hijacked by efforts to drum up criminal investigations of either candidate.”

Barr’s comments come as Trump has tweeted the word “OBAMAGATE” at least 10 times over the past eight days. The tweets began after the Justice Department dismissed its case against Trump’s former national security adviser Michael Flynn, who had pleaded guilty in 2017 to lying to the FBI.

Asked last week what specific crime he was accusing Obama of, Trump said, “You know what the crime is.”

“The crime is very obvious to everybody,” Trump told a Washington Post reporter at a news conference. “All you have to do is read the newspapers, except yours.”

The president has repeatedly accused Obama of “spying” on his campaign and his allies have sought to tie Trump’s predecessor to the Russia investigation to paint it as politically motivated.

Conservative backlash against Obama has ramped up after the former president recently criticized the Trump administration over its handling of the coronavirus pandemic. During a commencement address to students graduating from Historically Black Colleges and Universities, Obama on Saturday criticized the “folks in charge” for their handling of the coronavirus pandemic, though he did not mention Trump by name.

“More than anything, this pandemic has fully, finally torn back the curtain on the idea that so many of the folks in charge know what they’re doing,” Obama said in the address, which was streamed online. “A lot of them aren’t even pretending to be in charge.”

So far, about 90,000 Americans have died in the COVID-19 outbreak. Trump hit back Sunday, saying that while he hadn’t seen Obama’s remarks, the former president was “grossly incompetent.”

Trump last week publicly called on Senate Judiciary Committee Chairman Lindsey Graham, R-S.C., to bring Obama before his committee as it begins to hold hearings on the 2016 election.

“If I were a Senator or Congressman, the first person I would call to testify about the biggest political crime and scandal in the history of the USA, by FAR, is former President Obama,” Trump said. “He knew EVERYTHING. Do it @LindseyGrahamSC, just do it. No more Mr. Nice Guy. No more talk!”

But Graham threw cold water on that suggestion, saying he is “greatly concerned about the precedent that would be set by calling a former president for oversight.”

“No president is above the law,” Graham said. “However, the presidency has executive privilege claims against other branches of government.”

He said both Obama and Trump are “welcome to come before” his committee “and share their concerns about each other.”

“If nothing else it would make for great television,” Graham said. “However, I have great doubts about whether it would be wise for the country.”