Around 200 ethnic Uighurs from around the world gathered in Japan on Monday for a five-day meeting to press their case for independence from China.
Many Uighurs complain that they are the victims of state-sanctioned persecution and marginalisation in their homeland in northwest China, aided by the migration of millions of Han Chinese into the territory.
The resulting ethnic tensions have led to sporadic flashes of violence in the Xinjiang region, which is home to nine million Uighurs.
The exiled head of the World Uyghur Congress, Rebiya Kadeer told those assembled that Beijing's policy of "forcible assimilation" was unacceptable in a modern democracy.
"The Chinese government says it is assimilating and eventually eliminating the Uighur people and other indigenous people... meanwhile China is becoming a global power," she told the opening of the congress.
"We are peacefully struggling and hope the Chinese government will stop the repressing of Uighur people... and take political reforms to change their authoritarian rule.
"Chinese-style communism, Chinese-style human rights and Chinese-style democratisation is not up to date," said Kadeer, who lives in exile in the United States.
"The only thing left to China... is to embrace democracy and peace... and to stop the forcible assimilation of Uighurs and other peoples," she said, a reference to ethnic Mongols and Tibetans who have their own independence struggles.
China considers the WUC a "splittist" organisation and has condemned Japan's issuing of a visa for Kadeer, who last visited the country in 2009.
Kadeer said participants from more than 20 countries were at the meeting, which she said was being held in "the most democratic country in Asia".
Lawmakers from the centre-right opposition Liberal Democratic Party were at the meeting, along with an Italian politician and US rights activists.
The gathering comes after Japanese Prime Minister Yoshihiko Noda met his Chinese opposite number Wen Jiabao and South Korean President Lee Myung-Bak in a summit that focused on economic ties and the response to North Korea.
This year's conference will be the fourth after previous editions were held in Munich, Germany and in Washington.