The White House plans to fight the subpoena issued to former White House counsel Don McGahn by the House Judiciary Committee compelling him to testify about information in special counsel Robert Mueller’s report, The Washington Post reports. In an interview with the newspaper, President Trump said he opposed any of his former or current aides testifying in front of Congress because lawmakers were “obviously very partisan.” “I don’t want people testifying to a party, because that is what they’re doing if they do this,” Trump said. The president also claimed that he let his aides testify for Mueller’s report, so Congress has “all of that information that’s been given.” Sources told the Post that White House attorneys will tell lawyers for those called to testify that they will “be asserting executive privilege over their testimony.”

McGahn, who was mentioned more than 150 times in the Mueller report, provided investigators with instances in which Trump allegedly pressured him to fire Mueller—a claim that would support the obstruction of justice allegations the House Judiciary Committee is looking into. McGahn’s lawyer reportedly started talking to the committee on Monday about his client’s testimony, though a source told the Post that McGahn did not want to violate his “ethical obligations and legal obligations as a former White House official.”