One Uighur demonstration, which appears to have been quickly suppressed, took place in the town of Khotan on March 23, at the same time China was deploying thousands of security forces across a broad swath of its southwest to put down Tibetan unrest.

Officials said the protest was staged by Islamic separatist groups seeking to foment a broader uprising in Xinjiang. China often blames any ethnic disturbances on what it calls splittists and terrorists. Human rights groups say that Chinese Uighurs, like Tibetans, have fought for greater freedom to practice their religion as well as more autonomy.

The news of the protest in Xinjiang underscored the breadth of China’s problems with ethnic and religious minority groups in the country’s vast western regions, where there is a long history of unhappiness with Chinese rule. Ethnic groups Beijing has sought to pacify with economic development programs and suppress with heavy police presence appear to be using the upcoming Olympic Games, to be held in Beijing, as an opportunity to press their grievances and attract international attention to their causes.

“A small number of elements tried to incite splittism, create disturbances in the market place and even trick the masses into an uprising,” a statement published on the Web site of the Khotan government said in the first official acknowledgment of the disturbances. Uighur residents of Khotan reached by telephone either claimed not to understand Chinese or refused to talk about recent events there. But Han residents said that as many as 500 Uighurs protested in the center of the city. Some reports have said the Uighurs, who are Muslim, were objecting to restrictions on wearing Islamic scarves and head coverings. Some interviewees, however, said the protesters were seeking independence. Demonstrators were quickly arrested by security forces who took control of the area.

Zhu Linxiu, a senior police official in Khotan, declined to comment in detail about the incident, saying it was “inappropriate to publicise.” Two weeks before the reported protest in Khotan, China announced the discovery of what it called a terrorist plot in Xinjiang, which it said involved the smuggling of combustible liquids onto a commercial airliner by a Uighur woman who had spent time in Pakistan.