By Ben Blanchard

TAIPEI (Reuters) - Taiwan and Europe face the same threat from authoritarianism, President Lai Ching-te said on Thursday, marking 80 years since the end of World War Two in Europe and warning that indulging aggressors only whets their appetite for expansion.

Taiwan has faced increased military pressure from China, including war games, as Beijing seeks to assert its sovereignty claims over the democratically-governed island, and has sought joint cause with Europe from the risk it faces from Russia.

Speaking to an audience including European, British, Japanese, Canadian and U.S. diplomats based in Taiwan, Lai said Taiwan shares the same values as many of the democracies who fought in World War Two.

"At many points in history, people have thought to give the aggressor a small concession to earn peace," Lai said at the Taipei Guest House, the residence of the governor general under Japanese colonial rule of Taiwan, which ended in 1945.

"But as we all know from the painful lessons of World War Two, indulging aggressors with a taste of expansion only whets their appetite; it makes them more confident and hungrier for more."

Lai's speech - the first time Taiwan has formally marked the end of the war in Europe - coincided with Chinese President Xi Jinping's visit to Russia for Moscow's Friday military parade to mark the war's end.

In an article for a Russian newspaper on Wednesday, Xi said Taiwan legally belonged to China and no matter how the situation on the island evolved or "what troubles external forces may make", the trend towards "reunification" was unstoppable.

Lai did not directly mention Russia or China by name, but said Taiwan and Europe face "the threat of a new authoritarian bloc", pointing to issues like damage to undersea cables - which both Taiwan and Europe have complained about - election interference and spread of disinformation.

"Lovers of freedom around the world, both individuals and nations, must work together now in tight solidarity, before risks turn into crises and before crises are taken advantage of by those with ambitions for outward expansion," he said.

Lai, who took office in May last year, is condemned by Beijing as a "separatist". He says only Taiwan's people can decide their future, and rejects China's sovereignty claims.

(Reporting by Ben Blanchard; Editing by Michael Perry)