|Turkic Muslim Uighurs have long resented the presence of Han Chinese and political controls of Beijing [Reuters]
The Chinese government has claimed Muslim activists trained in Pakistan were behind weekend attacks that killed 11 civilians in the Xinjiang region.
In response, the autonomous regional government on Monday announced a crackdown on "illegal religious" activities at the start of the Muslim fasting month of Ramadan.
Ten civilians were killed in knife attacks and two small blasts during the weekend in Kashgar, a city in south Xinjiang, where the Uighurs, a Turkic Muslim ethnic minority, dominate.
The regional government said in a statement on Monday that a preliminary inquiry has shown "a group of religious extremists trained in overseas terrorist camps were responsible for the attacks".
The statement continued: "An initial police investigation found that the leaders of the group behind the attack had learned about explosives and firearms in Pakistan at a camp of the separatist East Turkestan Islamic Movement. This was another violent terrorist action by a small group of foes organised and planned under special conditions."
Captured suspects had confessed that the ringleaders had earlier fled to Pakistan and received firearms and explosives training before infiltrating back into China, the government website said.
It said: "Their malign intention behind this terrorist violence was to sabotage inter-ethnic unity and harm social stability, provoking ethnic hatred and creating ethnic conflict, splitting Xinjiang off from the motherland, casting the people of every ethnic group into a disastrous abyss."
Police shot dead five people and arrested four others after they stormed a restaurant, set in on fire after killing the owner and a waiter, and then ran onto the street and hacked to death four people, Xinhua news agency reported.
For the ruling Communist Party, the latest violence presents a test of its control in Xinjiang, where Uighur and Han Chinese residents view each other with suspicion.
Beijing has been wary of contagion from Arab uprisings inspiring challenges to party power in China.
After the attacks, the most senior Communist Party official in Xinjiang, Zhang Chunxian, announced a crackdown on religious extremism and vowed harsh punishment for those found guilty of attacks, according to
Xinjiang's official news website.
"[We will] resolutely attack religious extremist forces and effectively curb illegal religious activities," Zhang said.
Xinjiang has seen several outbreaks of ethnic violence in recent years as the mainly Muslim Uighur minority is unhappy with what they say has been decades of political and religious repression, and the unwanted immigration of China's dominant Han ethnic group.
This tension has triggered sporadic bouts of violence in Xinjiang - a vast, arid but resource-rich region which is home to more than eight million Turkic-speaking Uighurs.
In the nation's worst ethnic violence in decades, Uighurs savagely attacked Han Chinese in the regional capital, Urumqi, in July 2009 - an incident that led to retaliatory attacks by Han on Uighurs several days later.
The government says about 200 people were killed and 1,700 injured in the violence, which cast doubt on the authoritarian Communist Party's claims of harmony among the country's dozens of ethnic groups.
Yet, China sees Xinjiang as strategically vital, and Beijing has shown no sign of loosening its grip on the territory, which accounts for one-sixth of the country's land mass and holds deposits of oil and gas.