The White House says Ty Cobb plans to retire at the end of this month. Dowd, who subsequently quit Trump's legal team, confirmed to The Associated Press that Mueller's team had broached compelling Trump to testify.
Despite that, Trump wrongly tweeted on Tuesday that none of the leaked questions deal with any alleged "collusion" between his campaign and Russian Federation.
McCarthy said there are strong grounds for executive privilege.
Flynn was sacked February 13, 2017, after White House officials said he had misled them about his Russian contacts during the transition period by saying that he had not discussed sanctions. The person spoke on condition of anonymity to discuss private conversations.
Still, his retirement is the latest evolution for a legal team marked by turnover.
Sekulow also struggled to find another lawyer with experience in white-collar investigations to help after several high-profile lawyers turned down the work because of conflicts of interest or concerns about the negative publicity that could come from being involved.
Critical decisions lie ahead.
The questions attempt to drill down into Trump's conflicting public answers for his reasons for firing Comey - in one interview he referenced "this Russian Federation thing" - and ask him about the decision more directly.
Trump and his aides took comfort in recent assurances provided by Deputy Attorney General Rod Rosenstein that the president isn't a target of the Mueller investigation or of a separate probe into Trump's longtime lawyer, Michael Cohen, according to people familiar with the matter.
It's unclear if Trump will actually be subpoenaed.
Mueller's prosecutors and Trump's lawyers have been negotiating the terms of a voluntary interview, but Mueller is now threatening a subpoena if Trump does not commit to the session. Mueller is probing not only Russian election interference and possible coordination with Trump associates but possible obstruction of justice by Trump.
Mr Mueller, who is leading the investigation into Russian meddling in the 2016 presidential campaign, believes he has legal standing to subpoena a sitting president, even though such a move has never been fully tested, the officials said.
"What are they afraid of?"
"At some point, I will have no choice but to use the powers granted to the Presidency and get involved!" said Trump in a Wednesday morning Twitter post.
It's also not clear whether the leak of the questions was meant to somehow influence whether Trump will do the interview.
The Justice Department says that "dozens of members and staff from both parties" have viewed thousands of classified documents and House staff members have temporary office space in the department to review additional materials.