Dozens of pro-democracy activists gathered in Japan Friday to call for global pressure on Beijing, days ahead of the 25th anniversary marking the brutal crushing of the Tiananmen Square protests.

"There used to be legitimacy in the Chinese government that was based on an ideal. But since the 1989 crackdown, there is no such a thing," Wu'er Kaixi, one of the leaders of the ill-fated protest, said in the meeting.

"The Chinese Communist party has been ruling people with fear," he told activists from Taiwan, Hong Kong, Australia and other regions.

The meeting opened a three-day event in Tokyo comprising symposiums and a demonstration aimed at drumming up support for their movement, ahead of the June 4 anniversary.

Wu'er Kaixi, who lives in self-imposed exile in Taiwan, became a celebrity when he interrupted China's then-premier Li Peng -- regarded as the mastermind of the Tiananmen operation -- during a televised meeting between student leaders and politicians in May 1989.

A member of the Uighur ethnic minority, Wu'er Kaixi was number two on the government's "most-wanted" list of student protesters following the military crackdown, which left hundreds, possibly thousands, dead.

China's present-day leaders know the nation's astonishing economic and military transformation means Western nations are reluctant to challenge their authoritarianism, said Wu'er Kaixi.

"I beg citizens of foreign countries, please put more pressure on China over its human rights record. At least do not stand on the wrong side," he said.

Chen Pokong, who helped spread the protest movement to southern China, said Japan should not be afraid to speak out on human rights.

"Japan should be a role model in showing a democratic value," said Chen, who now lives in the United States. "To me Japan is too worried about harming its relations with China."

Activists said the situation in China has worsened since 1989.

Hu Yuan-Hui, associate dean of National Chung Cheng University in Taiwan, said fear is widespread among journalists in mainland China as well as in Taiwan, over violent attacks by unidentified criminals.

Li Song, director of the Japan branch of the Federation for a Democratic China, told AFP: "Despite some freedom of expression seen with the Internet, such as in Weibo (China's Twitter-like microblog platform), we don't know what constitutes a red line for the Chinese authorities."

"Journalists or activists are suddenly attacked or arrested for unknown reasons," he said.

The meeting was a rare opportunity for pro-democracy activists to gather in Japan, where people show only modest interest in human rights issues abroad as compared with the West, he said.

"Japan is a very important base for our pro-democracy movement," Wu'er Kaixi told AFP, despite tensions between the two countries over disputed islands.

"Democracy should not be based on nationalism," he said, it "should be based on the recognition that it is a universal value."