Leading Russian chess grandmaster Sergey Karjakin has been suspended from playing for six months for publicly supporting Russia's invasion of Ukraine, the game's world governing body FIDE announced Monday.

The organisation's ethics committee found that Karjakin, who in 2016 challenged world champion Magnus Carlsen for the title, had brought the game into disrepute with his comments on social media.

The 32-year-old player is an outspoken supporter of Russian President Vladimir Putin.

His statements "on the ongoing military conflict in Ukraine has led to a considerable number of reactions on social media and elsewhere", most of the rejecting Karjakin's views, said FIDE.

Karjakin had published a letter backing Russia's intervention, saying he hoped it would achieve the "demilitarization and denazification of Ukraine" echoing the position taken by Moscow, the ruling noted.

Karjakin also tweeted pictures of what he said were Ukrainian soldiers holding a photo of Adolph Hitler, commenting: "This is Ukraine," the ruling added.

Karjakin is ranked 18 in the world rankings
Karjakin is ranked 18 in the world rankings ANP via AFP / Koen Suyk

Karjakin is currently ranked 18th in the world. But the ban means he will not be able to take his place as one of the eight players at the Madrid candidates tournament in June to compete for the right to challenge Carlsen for the title.

On Monday, Karjakin denounced what he said was FIDE's "shameful" ruling, posting from his Telegram account.

"I regret nothing," he wrote, saying he was first and foremost a patriot and a chess player second.

Russia's chess federation has already said it will appeal the ruling, denouncing what it said was "discrimination".

Last Wednesday, FIDE suspended the Russian and Belarusian national teams from chess tournaments, while allowing individual players from those countries to continue to compete.

Monday's ruling cleared another Russia player, Sergei Shipov, of similar charges, saying his comments had been less provocative than those of Karjakin, and that he was not as well known and so had far less of an audience.