George Papadopoulos, a former adviser to President Donald Trump's campaign, called for former FBI director James Comey to publicly testify about the FBI's purported mishandling of the Russia investigation.

Papadopoulos' tweets came after House Republicans subpoenaed Comey and former attorney general Loretta Lynch to appear before lawmakers in a closed-door session.

But Comey has already been pushing for an open hearing.

Papadopoulos earlier wanted immunity to testify before the Senate Intelligence Committee, but said Saturday that he'll withdraw his request if Comey testifies publicly.

George Papadopoulos, the former foreign-policy aide to President Donald Trump's campaign who pleaded guilty in the Russia investigation last year, took to Twitter on Saturday to call for the former FBI director, James Comey, to testify publicly about the FBI's purported mishandling of the Russia probe.

"If Jim Comey wants to testify in public and tell America who/why in Trump’s advisory board was under FISA; who Joseph Mifsud is; if the FBI had any role in my dealings with Charles Tawil; and explain the UK and Australia’s surveillance role," he tweeted, "that would be good for the country."

But Comey has been asking to testify publicly from the start.

Earlier this week, House Republicans — who will be a minority in the lower chamber of Congress come January — made a last-minute push to subpoena Comey and former attorney general Loretta Lynch.

Comey acknowledged the news Thursday, tweeting, "Happy Thanksgiving. Got a subpoena from House Republicans. I'm still happy to sit in the light and answer all questions. But I will resist a 'closed door' thing because I've seen enough of their selective leaking and distortion. Let's have a hearing and invite everyone to see."

Democrats have also called for an open hearing, though Republicans are pushing for a closed-door session as they continue their investigation into whether the FBI allowed anti-Trump bias to affect its handling of the ongoing Russia investigation.

James Comey. Win McNamee/Getty

Papadopoulos, meanwhile, reportedly wanted immunity in exchange for testifying before the Senate Intelligence Committee. Legal experts said the request indicated the former Trump aide may be worried his testimony could implicate him in a crime.

Read more: George Papadopoulos dumped by his own lawyers as the former Trump aide embarks on a 'self-defeating gambit'

But Papadopoulos backed away from his request Saturday.

"If Jim Comey agrees to answer the below questions in a public testimony, I will agree to testify to the senate without immunity," Papadopoulos tweeted. "It’s a win-win for the country. America first."

Papadopoulos pleaded guilty to one count of lying to the FBI last year and agreed to cooperate with prosecutors. At his sentencing hearing in September, he expressed remorse for his actions, saying he was "grateful" for the opportunity to help the investigation and had "nothing but respect for the Court and the legal process."

But the former Trump aide soon adopted a very different tone.

After his sentencing hearing, Papadopoulos tweeted that the FBI's investigation was "the biggest case of entrapment!" The next day, Papadopoulos said he was considering withdrawing his guilty plea because he believed he was framed.

Several days later, he tweeted that he had been sentenced "while having exculpatory evidence hidden from me."

He added that if he had known that at the time, he never would have pleaded guilty. And on November 9, Papadopoulos tweeted that his "biggest regret" was pleading guilty.

He has since deleted those tweets.

Read more: Mueller used George Papadopoulos' own tweets against him in a new court filing

Robert Mueller. Alex Wong/Getty Images

Papadopoulos hired new lawyers in September as he and his wife took to Twitter and the media to promote the unfounded theory that he was entrapped by the FBI, who he said wanted to "infiltrate" and "sabotage" the Trump campaign.

Earlier this month, Papadopoulos' former defense lawyers filed a motion pulling out from representing him.

DOJ veterans pointed out that it's unusual for lawyers to file paperwork to formally withdraw from a case.

Elie Honig, a former prosecutor from the Southern District of New York who specialized in organized-crime cases, said it was likely that Papadopoulos' "lawyers are trying to disassociate with him because of the conspiracy theories he's spreading, or perhaps they told him to knock it off, and he's not listening."

If Papadopoulos is seriously considering withdrawing his guilty plea, he would have to show a judge he was somehow misled or coerced into pleading guilty, and that the plea was not fully voluntary. On a practical level, that would set a defendant up to argue that his lawyers didn't explain the full terms of the plea correctly or lied to him.

In that case, Papadopoulos' lawyers may also have withdrawn because they'd no longer be able to represent him due to a conflict of interest.

Withdrawing a guilty plea is extraordinarily difficult. And if Papadopoulos does succeed, he may find himself in deeper trouble than he was in before because his indictment would resurface and he would not have the option of pleading guilty with an agreement to cooperate.