"This is already World War III," says Garry Kasparov, former world chess champion and one of Vladimir Putin's most vocal critics as Russia continues its invasion of Ukraine.
In a series of tweets on Thursday, Kasparov has warned the NATO countries that Putin will bring upon them "an even greater catastrophe".
"We are witnessing, literally watching live, Putin commit genocide on an industrial scale in Ukraine while the most powerful military alliance in history stands aside... This is already World War III. Putin started it long ago & Ukraine is only the current front," said Kasparov, one of the most-feared chess players of all time.
Now retired from active chess and living in New York for the last nine years for fear of retribution from the Kremlin, Kasparov has though never shied away from attacking Putin.
"There is no waiting this out. This isn't chess; there's no draw, no stalemate. Either Putin destroys Ukraine and eventually hits NATO with an even greater catastrophe, or Putin falls in Russia. He cannot be stopped with weakness," Kasparov tweeted.
Kasparov, who is Russian, has reiterated that "Putin vows to exterminate Ukrainians while we watch".
"As I said in 2014 and a fateful week ago, the price of stopping a dictator always goes up. What would have been enough to stop Putin 8 years or 6 months or 2 weeks ago is not enough today, and the price will rise again tomorrow. Fight. Find a way."