Chinese police have jailed an outspoken Uighur journalist for allegedly endangering national security, a colleague said Friday, adding to the scores of detentions reported in the restive Xinjiang region since deadly ethnic rioting erupted there four months ago.

Well-known academic Ilham Tohti said Hailaite Niyazi, the former manager of his Web site, was taken from his home in the regional capital of Urumqi on Oct. 1. He said Niyazi's family was informed Oct. 4 that he was suspected of endangering national security.

Tohti said Niyazi's wife believes the allegation is linked to interviews Niyazi gave to foreign media following the riots that broke out July 5.

Uighurs are a Turkic Muslim ethnic group linguistically and culturally distinct from China's majority Han.

The July riots, in which Uighurs attacked Han, who then launched revenge attacks days later, killed nearly 200 people in China's worst ethnic unrest in decades. Hundreds of people have been rounded up since and the government has smothered much of Xinjiang with security.

Xinjiang's High Court on Friday upheld death penalties for nine people convicted earlier this month of committing murder and other crimes during the riots, the official Xinhua News Agency reported. The decisions still require a Supreme Court review.

China blames the rioting on overseas-based groups agitating for greater Uighur rights in Xinjiang, but has presented no direct evidence.

One of those figures blamed by Beijing, exiled Uighur activist Rebiya Kadeer, said Friday during a visit to Tokyo that there should be an independent investigation into the treatment of Uighurs since the riots. She denounced the death sentences handed down so far, saying the accused have been denied due legal process.

"The international community must investigate what has been happening since July 5 in Uighur areas," she said in a speech to the Foreign Correspondent's Club.

Kadeer has also condemned as unfair reports of a closed eight-hour trial in Xinjiang's remote Yili city last week where 19 Uighur men were convicted of endangering state security for planning a protest in Yili the day after the Urumqi riots.

The men allegedly bought gasoline and clocks with the intention of making explosives, state media said last week. Although they abandoned the plan due to the high level of security in Yili, they alleged leader of the group was sentenced to life in prison while the other men were sentenced to between three and 15 years in jail, the Yili News Net report said.

Endangering state security is a vaguely worded charge often used in China to silence dissident voices.

A woman with the Xinjiang Public Security Department said she was unable to confirm the journalist, Niyazi, had been detained and refused to give her name.

During an interview with The Associated Press on July 9, Niyazi was cautiously critical of the regional government's inability to tolerate dissent.

"In China, sometimes even if you are just defending human rights, if you say something a little bit extreme, you'll be in trouble," he said.

Tohti said he didn't publicize the detention earlier because he thought it would damage his friend's case.

Niyazi, 50, was a manager and editor for Tohti's Uighurbiz Web site until June of this year and has also worked for the state-run newspapers Xinjiang Legal News and the Xinjiang Economic Daily.

Tohti, a Beijing-based economics professor, was himself detained after the riots for more than a month of questioning by secret police but not charged.

Web sites such as Tohti's were accused by the government of whipping up Uighur fury and organizing the July unrest.

Internet service in Xinjiang was shut down shortly after the riots and the region remains largely offline, to the frustration of many residents and businesses.

Along with Tohti's Uighurbiz, authorities also targeted Diyarim.com, whose manager Dilixiati Paerhati was taken from his apartment on Aug. 7 by unidentified men and has not been heard from since, according to an Amnesty International statement last week that cited his older brother.

"He only edits a Web site, he hasn't done anything wrong," Dilixiati Paerhati's brother, Dilimulati, a student in England, was quoted as saying by the group. "There has been trouble in Xinjiang but my brother wasn't part of it," he said.