Washington (CNN) President Donald Trump indicated Thursday that he's not willing to allow former White House counsel Don McGahn -- a key figure in the Mueller report and Trump's efforts to obstruct the investigation -- to testify before Congress.

"I've had him testifying already for 30 hours and it's really -- so I don't think I can let him and then tell everybody else you can't, " Trump said Thursday. "Especially him, because he was a counsel, so they've testified for many hours, all of them, many, many, many people. I can't say, 'Well, one can and the others can't.' I would say it's done."

"We've been through this. Nobody has ever done what I've done. I've given total transparency," he added. "(Congress) shouldn't be looking anymore."

On Sunday, White House counselor Kellyanne Conway told CNN's Jake Tapper on "State of the Union" that Trump could use executive privilege to block McGahn from complying with a congressional subpoena.