Conor McGregor's preparations for his lucrative showdown with Floyd Mayweather Jr have been dealt a blow after Paulie Malignaggi sensationally quit the feisty Irishman's training camp.

Two-weight world champion Malignaggi was left incensed after photos emerged on social media showing him on the canvas during a sparring session with UFC star McGregor.

Malignaggi stated that the pictures were a misrepresentation of what occurred in the ring and called on McGregor to release footage of the session.

The American insists that he and McGregor maintain professional respect for one another, but will no longer be helping him prepare for his fight with Mayweather, which is expected to earn McGregor $75million.

Speaking to ESPN, Malignaggi said: "Conor on the inside, he can get a little rough. He shoved me down, you know, but no knockdowns.

"Obviously, 12 rounds, you're going to see there's a mark on my face. Very, very hard work for both of us. 

"I was starting to get in a groove in the middle rounds, starting to land some good shots. Conor really came on strong in the end. It was back and forth.

"I won't release any information about his game plan or what he's working on - I wouldn't do that. But this has become a fiasco. It's a circus.

"And I do want that sparring video released. The UFC's PI definitely has that video. I understand it can't come out now, but Conor, if you have any balls, release what really happened."

  Another handy 12 rounds today. We are prepared to destroy Floyd. Pick whatever size gloves you want as well little man. I fight with 4oz. I don't give a fuck about the size of the glove. I am coming sprinting at you with bricks. Know that. Brittle hands. A post shared by Conor McGregor Official (@thenotoriousmma) on Aug 2, 2017 at 4:27am PDT

Earlier this week, esteemed referee Joe Cortez said McGregor and Malignaggi had to be told to "calm down" during a heated session.

Malignaggi wished McGregor well for the rest of the camp, but vowed to air his full version of events when the time is right.

He added via a statement: "I just wanted to clear the air. I am leaving the McGregor training camp today. I came with the best intentions and intended to help out. Just being a part of such a big event in this capacity excited me. I believe Conor and I have a mutual respect inside the ring, earned from each other with some good work over two sparring sessions. 

"It's some stuff outside the ring and some ways some things were handled in training camp that I didn't agree with that made me come to this decision. It's not my place to dictate terms in a training camp that is not mine, but it's my place to decide if I want to be part of it. I will not give away anything tactical that I saw in two sparring sessions with Conor. 

"For what it's worth, they have my word. The things that upset me though I will speak about it in time. I wish team McGregor well in the rest of their preparations and look forward to being back in Vegas to work fight week on Showtime."