Exiled Uyghur leader Rebiya Kadeer has arrived in Japan despite China's displeasure, and China in response strongly condemned Japan for allowing the visit as she was accused of instigating the deadly ethnic riots in Xinjiang.
Kadeer left the United States, where she lives in exile, for a five-day visit in Japan and is expected to hold a press conference on Wednesday and speak at a symposium.
She is likely to talk about the unrest in northwestern Xinjiang region earlier this month.
China claims that almost 200 people, mostly ethnic Han Chinese, died of the riot; Kadeer, however, said that thousands have died, killed on masse by police.
China says Kadeer, the once successful businesswoman in China but now leader of exile group the World Uyghur Congress, planned the outbreak of violence.
Kadeer denies the claim.
Kadeer is also expected to meet members of Prime Minister Taro Aso's party, but the contact will be unofficial for security reasons.
Beijing had called on Tokyo to deny Kadeer's entry visa.
Through its spokesman Qin Gang, China's Foreign Ministry expressed its dissatisfaction with the trip.
Beijing criticized Kadeer as a dangerous terrorist involved in separatist activities, including the violent protests in Xinjiang on July 5.
Because of similar charges she had spent around six years in a Chinese prison before being released under international pressure in 2005.
China's ambassador to Japan, Cui Tiankai, also warned that a visit by this criminal would damage a working relationship between the two countries which has improved recently, after years of diplomatic spats over wartime history.
We must prevent important matters that should be worked on together from being disturbed by a criminal or attention to our common interests from being diverted, Kyodo quoted Cui as saying.
By contrast, in recent weeks Japan criticized China's crackdown in Xinjiang, calling on Chinese authorities to protect the human rights of Uyghur people, AsiaNews reported on Tuesday.
In Xinjiang, which is still under martial law, internet access has been restored on Tuesday, but only to a few select government and business-related Web sites; all the other are still being blocked.
Well-known social networking sites like Facebook and Twitter have been blocked nationwide for weeks to prevent the spread of the domestic unrest.
Hackers have also defaced the website of Australia's biggest film festival which refused to withdraw a documentary about Kadeer, Reuters quoted organizers as saying on Monday.
The Chinese government two weeks ago protested to the Melbourne International Film Festival over the inclusion of the documentary and last week three Chinese films were withdrawn in protest at Kadeer's planned attendance at the Aug. 8 premiere, Reuters said.