WARSAW, Poland -- Russian chess master and political activist Garry Kasparov compared President Vladimir Putin's "one-man dictatorship" to the rule of Adolf Hitler on Thursday, warning that if the West fails to stop him now the price to do so could rise.

Kasparov also argued that Western leaders should not try to appease Putin in a search for strategic ground with him on issues such as Iran's nuclear program and the fighting in Syria and Iraq, because Putin has no real interest in compromise and instead needs instability to try to justify staying in power.

"Pretending that Putin has a certain strategic interest that can be shared, it's wrong. I don't see any real strategic issue where his interest could be common with Europe," Kasparov said at the Warsaw Security Forum.

Kasparov, who now lives in New York and is the chairman of the Human Rights Foundation, called on Western leaders to recognize that Putin is a threat and to show greater resolve in pressuring his regime.

"I don't know what the price of confronting Mr. Putin is today. It could be high. But what I know from history (is that) tomorrow the price will be higher. In 1936, to stop Hitler would be one price; in '37 it's different; in '38 high; in '39 too late."

He also said that Putin considers it a sign of weakness that Western leaders have stressed that they will not consider military solutions.

Kasparov has played a leading role in Russia's liberal opposition movement and helped stage protests against President Vladimir Putin's rule. He fell out with some other opposition leaders, and in 2013 said he has no intention of returning to Russia but vowed to continue fighting against Putin's government from abroad.