Ex-Illinois Gov. Rod Blagojevich again proclaimed himself a "political prisoner" Friday night in a heated interview with CNN's Anderson Cooper.

Blagojevich, a one-time contestant on "The Celebrity Apprentice," was convicted in 2011 of federal charges of using his powers as governor to extract campaign money and other political favors in exchange for naming a successor to fill the Illinois Senate seat left open when Barack Obama became president.

Blagojevich walked out of federal prison Tuesday after President Donald Trump commuted his 14-year sentence. He served nearly eight years.

"I am a political prisoner," Blagojevich said on CNN, echoing claims he made earlier in the week.

Cooper wasn't having it.

"Wait a minute, you're a political prisoner? Nelson Mandela was a political prisoner. Political prisoners have no due process and are unjustly jailed," Cooper said. "You're hardly a political prisoner."

Blagojevich was charged with corruption and removed from office in 2009 by a unanimous vote in the Illinois Senate. He was indicted by a federal grand jury and convicted in 2011 on 17 charges, including trying to extort a children's hospital for contributions. In 2015, he appealed his case to the Seventh Circuit in Chicago, which called the evidence against him "overwhelming." The Supreme Court twice denied to take up Blagojevich's appeal.

Nelson Mandela, the former president of South Africa, spent 27 years in prison for fighting apartheid and won the Nobel Peace Prize in 1993.

'Freed political prisoner':Rod Blagojevich speaks after Trump commutes sentence

Blagojevich responded to Cooper by saying that Mandela had, in fact, been convicted in a court of law. Cooper fired back that Mandela had been convicted "by a racist apartheid government, and not a jury of his peers."

"As someone who's worked in South Africa and saw apartheid, the idea that you are comparing yourself to somebody that has actually been railroaded by an apartheid system, it just nuts and, frankly, offensive," Cooper said.

Blagojevich repeatedly said Cooper was "putting words in his mouth." He claimed that he was sent to prison by "a handful of corrupt prosecutors who were abusing their power."

"I was thrown in prison and spent nearly eight years in prison for practicing politics – for seeking campaign contributions without a quid pro quo," Blagojevich said.

Blagojevich compared the investigation of his case to "a dirty cop planting a murder weapon."

Cooper pressed Blagojevich to admit guilt, but Blagojevich maintained his innocence.

"You got out. You do have an obligation to at least admit what you did wrong, and you refuse to do that. And you're creating a whole new alternate universe of facts," Cooper said.

Blagojevich was one of four people to receive commutations, or reduced prison sentences, from the president this week. Trump granted pardons to seven others. Some had political ties to the president's allies; others have become advocates for changing the criminal justice system.

Trump clemency spree:Who got pardoned, who got shorter prison sentences?

Follow Grace Hauck on Twitter @grace_hauck.