Magnus Carlsen flatly accused Hans Niemann of cheating in a lengthy statement Monday.

Carlsen, the No. 1-ranked chess player in the world, explained his decision to withdraw from the Sinquefield Cup earlier this month and resigning from their Julius Baer Generation Cup match with Niemann after one move.

Niemann has faced cheating allegations — from anything to wireless vibrating anal beads to a vibrating shoe, according to multiple reports — in the past and the rumors took the internet by storm with Tesla CEO Elon Musk even chiming in at one point.

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Magnes Carlsen at the FIDE champonship

Magnus Carlsen (NOR) during the FIDE Chess World Rapid & Blitz 2021 in Warsaw, Poland, on Dec. 28, 2021. (Foto Olimpik/NurPhoto via Getty Images)

While Carlsen has alluded to the cheating rumors as the reasons why he resigned from his latest match against Niemann, he pointed directly to that in the statement

"I know that my actions have frustrated many in the chess community. I’m frustrated. I want to play chess. I want to continue to play chess at the high level in the best events," he said.

"I believe that cheating in chess is a big deal and an existential threat to the game. I also believe that chess organizers and all those who care about the sanctity of the game we love should seriously consider security measures and methods of cheat detection for over the board chess. When Niemann was invited last minute to the 2022 Sinquefield Cup, I strongly considered withdrawing prior to the event. I ultimately chose to play.

"I believe that Niemann has cheated more — and more recently — than he publicly admitted. His over the board progress has been unusual, and throughout our game in the Sinquefield Cup I had the impression that he wasn’t tense or even fully concentrating on the game in critical positions, while outplaying me as black in a way I think only a handful of players can do. This game contributed to changing my perspective.

"We must do something about cheating, and for my part going forward, I do not want to play against people that have cheated repeatedly in the past, because I don’t know what they are capable of doing in the future.

Magnus Carlsen in August 2022

Norways Magnus Carlsen gestures during his Round 8 game against the Slovakia team at the 44th Chess Olympiad 2022, in Mahabalipuram on Aug. 6, 2022. (ARUN SANKAR/AFP via Getty Images)

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"That is more that I would like to say. Unfortunately, at this time I am limited in what I can say without explicit permission from Niemann to speak openly. So far I have only been able to speak with my actions, and those actions have started clearly that I am not willing to play chess with Niemann. I hope that the truth on this matter comes out, whatever it may be."

FIDE, the International Chess Federation, said Carlsen shouldn’t have resigned given his status as world champion while also acknowledging the need to fight cheating.

"First of all, we strongly believe that the World Champion has a moral responsibility attached to his status, since he is viewed as a global ambassador of the game. His actions impact the reputation of his colleagues, sportive results, and eventually can be damaging to our game. We strongly believe that there were better ways to handle this situation," FIDE said.

"At the same time, we share his deep concerns about the damage that cheating brings to chess. FIDE has led the fight against cheating for many years, and we reiterate our zero-tolerance policy toward cheating in any form. Whether it is online or ‘over the board’, cheating remains cheating. We are strongly committed to this fight, and we have invested in forming a group of specialists to devise sophisticated preventive measures that already apply at top FIDE events."

Niemann hasn’t directly addressed Carlsen’s letter.

Magnus Carlsen in 2018

Magnus Carlsen vs. Fabiano Caruana, London, Britain, Nov. 26, 2018, Norway's Magnus Carlsen during round 12 of the World Chess Championship Final. (REUTERS/Paul Childs)

He denied cheating in an interview with the Chess Club earlier this month.

"I have never cheated in an over-the-board game. That is the worst thing I could do: cheat in a tournament with prize money," he said, via KSDK-TV. "You know my dream came true. I lived my dream for a day beating Magnus, and then, all of this happened."

Niemann had been accused of cheating in the past — both times while playing online when he was younger. 

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He’s said he’s never "cheated in an over-the-board game," according to the Guardian.