World chess champion Magnus Carlsen has spoken at length about his withdrawal in a duel with Hans Niemann and accused the American of cheating.

In essence, Carlsen confirms reports from the past few weeks that Niemann is said to have cheated in the game against him.

However, he is not allowed to say more at the moment, even if he would like to go into more detail, the 31-year-old Norwegian wrote on Twitter on Monday evening.

"I hope the truth will come out, whatever it may be."

"Need to do something"

According to Carlsen, he believes "that Niemann cheated more often (...) than he publicly admitted." However, there is no evidence that the 19-year-old grandmaster Niemann cheated.

Carlsen wrote: "We must do something about cheating in chess.

I will help by not playing against players who have cheated in the past as I am not sure what such players will do in the future."

The first incident between the competitors occurred at the beginning of September.

At the Sinquefield Cup in St. Louis, the superstar surprisingly lost to Niemann and withdrew from a tournament for the first time in his career.

The 31-year-old Norwegian did not give any reasons at the time.

The chess scene interpreted Carlsen's exit as an allegation of fraud against Niemann.

The American admitted in an interview during the Sinquefield Cup to having cheated twice in online games as a teenager, aged 12 and 16, but never in person at the chessboard.

Carlsen now opined that Niemann's progress in on-site games was unusual.

"During our game at the Sinquefield Cup, I got the impression that he wasn't fully focused and focused on the game at the crucial stages, while he was dominating me with the black checkers in a way that only a small group of people could believe know.

The Sinquefield Cup game helped change my perspective on the subject,” said Carlsen.