Attorney General William Barr on Wednesday said he did not know whether President Donald Trump or any other White House official had ever suggested to him that the Department of Justice launch an investigation into someone.

The comments came in a tense exchange with Sen. Kamala Harris, D-Calif., who launched a bid for president earlier this year, during Barr's testimony before the Senate Judiciary Committee.

"Has the president or anyone at the White House ever asked or suggested that you open an investigation of anyone? Yes or no, please, sir," Harris, the former California attorney general, asked Barr.

"Seems you would remember something like that and be able to tell us," Harris said.

Barr told Harris that he was trying to "grapple with the word 'suggest.'" The White House, he said, had not asked him to open an investigation.

"Perhaps they have suggested?" Harris asked.

"I don't know. I wouldn't say 'suggest,'" Barr said.

"Hinted?" Harris asked.

"I don't know," Barr said.

Last spring, Trump told then-White House counsel Don McGahn that he wanted to order the Justice Department to prosecute his 2016 electoral rival Hillary Clinton as well as former FBI Director James Comey, The New York Times reported last year.

But McGahn pushed back, the outlet reported, and had White House lawyers draft a memo outlining the possible consequences of such a move, which they wrote could include accusations of abuses of power, as well as impeachment.

The Times reported that it was not clear whether Trump kept pushing for the prosecutions but that he did continue to discuss the matter. McGahn left the Trump administration in October.

Barr was confirmed as attorney general in February. On Wednesday he took questions from lawmakers about special counsel Robert Mueller's report on the Justice Department's investigation into Trump's 2016 campaign.

Following her exchange with Barr, Harris told reporters that the attorney general "lacks all credibility." She called on him to resign.

The White House did not respond to a request for comment.

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