Human rights advocates have often accused Chinese communist authorities of using anti-terrorism laws to persecute members of the largely Muslim Uighur ethnic group in Xinjiang. Xinjiang is home to most of China's Uighurs and a region some would like to see be independent from China under the name East Turkestan.
Exiled Uighur advocates say they have been getting reports from Xinjiang saying authorities have been rounding up suspected Uighur separatists over the past few weeks.
They say the arrests, plus warnings by Communist Party officials in recent days, signal a possible crackdown ahead of two anniversaries: September 11, and October 1, which will mark 50 years since the Chinese Communist government took over Xinjiang.
The Communist Party leader in Xinjiang, Wang Lequan, in recent days announced the government would clamp down on Xinjiang separatists, whom Beijing labels as terrorists.
"Those forces are engaging in activities aiming to split China and sabotage the unification of the motherland, jeopardizing national security, and endangering the interests of ethnic groups," said Wang Lequan. "I think any country in the world would firmly crack down on these serious crimes, and that is why we must take tough measures."
Some Uighur activists are pushing for greater autonomy for Xinjiang while others, especially those overseas, want complete independence for the region.
There is one militant Uighur independence group, the East Turkestan Islamic Movement, blamed for a number of bombings and violent protests in Xinjiang. It was declared a terrorist group by the U.S. State Department in 2002 and has largely been dormant since then.
Ahmet Igamberdi is an Uighur exile based in Australia who identifies himself as the president of a government in exile that was proclaimed last year. He says he sees the arrests and warnings as examples of how the Beijing government is using anti-terrorism laws to persecute Uighurs and attack their culture.
"China's government calls some of our people terrorists, but Chinese government using this using this [as a] pretext," said Ahmet Igamberdi. "Chinese government [is] implementing a genocide policy on Uighur people: cultural genocide; religious genocide; economic genocide."
Uighurs say China's national policy of assimilation is destroying their traditional culture. At issue is the government's movement of the ethnic Han majority into minority areas such as Xinjiang and the required instruction and usage of the national language, Mandarin.
Xinjiang Communist Party chief, Wang Lequan, on Friday accused Uighur activist Rebiya Kadeer - now exiled in the United States - of plotting with terrorist groups to disrupt the October 1 anniversary - a claim she has dismissed.
Mrs. Kadeer spent more than five years in prison on charges of endangering state security after she sent newspaper clippings to her husband in the United States. Following repeated requests from Washington, China released her in March of this year just before a visit to Beijing by U.S. Secretary of State Condoleezza Rice.