More than 30 people were killed and scores injured on Thursday when two vehicles ploughed into a market and explosives were thrown in China's restive Xiniiang region. The vast, resource-rich far-western region has seen periodic violence which has increased and sometimes spread beyond it in recent months. Beijing says it faces terrorism from a violent separatist movement there, driven by religious extremism and foreign groups.
Here are five things you need to know about Xinjiang and the Uighurs issue.
1. What is Xinjiang and who are the Uighurs?
Xinjiang is a region in the western-most edge of northern China. It is home to an ethnic Muslim minority called Uighurs (also often spelled Uyghurs) who have long chafed under Chinese rule and the steady influx of ethnic Chinese into the region.
Xinjiang shares borders with Mongolia, Russia, Kazakhstan, Kyrgyzstan, Tajikistan, Afghanistan, Pakistan and India.
Uighurs are a Turkic-speaking people who regard themselves as culturally and ethnically close to central Asia, despite a long history of Chinese rule.
Since the collapse of the Qing dynasty in 1912, Xinjiang, which means "new frontier" in Chinese, has enjoyed varying levels of autonomy.
In 1933, rebels declared independence and created the short-lived Islamic Republic of East Turkistan.
The Chinese Communist Party took over the territory in 1949 and in 1955 it was declared an autonomous region, giving it a status similar to that of Tibet, which lies to the south of Xinjiang.
2. What do Uighurs in Xinjiang want?
Over the decades, waves of Han Chinese migrants arrived in the region, displacing Uighurs from their traditional lands and fueling tensions.
Xinjiang is now home to more than eight million Han Chinese, up from 220,000 in 1949, and 10 million Uighurs. The newcomers take most of the new jobs, and unemployment among Uighurs is high.
They complain of discrimination and harsh treatment by security forces, despite official promises of equal rights and ethnic harmony.
Activists say that a campaign is being waged to weaken the Uighurs' religious and cultural traditions and that the education system undermines use of the Uighur language.
Separatists who want outright division from China call the Xinjiang region "East Turkestan" and want independence from China and the right to self-govern.
3. Why is China concerned about the Uighurs?
Simmering tensions have erupted into riots. In July last year, 35 people were killed in a town about 250 kilometres south-east of the provincial capital Urumqi. State media said "knife-wielding mobs" attacked government buildings.
The worst violence in decades took place in July 2009, when rioting in Urumqi between Uighurs and Han Chinese killed some 200 people and injured 1,700. That unrest was followed by a crackdown by security forces.
Beijing says Uighur groups want to establish an independent state and, because of the Uighurs' cultural ties to their neighbours, leaders fear that elements in places like Pakistan may back a separatist movement in Xinjiang.
After the Sept 11, 2001 terror attacks in New York and Washington, some 22 Uighurs were rounded up in Pakistan and Afghanistan and detained in Guantanamo Bay. Most have been released and cleared of wrongdoing.
China has found it useful to blame ethnic tensions on outside interference, undermining sympathies at home for legitimate grievances, analysts say.
4. How bad has the Xinjiang-related violence become?
Hundreds are believed to have died in recent years, but what is different now is that the violence is entering a new phase with the emergence of these targeted terrorist strikes.
Ethnic rioting and clashes in Xinjiang reached a peak four years ago, causing roughly 200 deaths and triggering a crackdown by local authorities. Renewed protests last year also turned violent and are believed to have claimed more than 100 lives.
Recent attacks like the Kunming mass knifing in March, however, mark the first time in the modern era that large-scale violence have reached China's biggest cities.
The most public and shocking attack on the Chinese came in October last year when a jeep veered into a crowd in Beijing's iconic Tiananmen Square, then crashed and burst into flames, killing five people. Almost immediately, the authorities declared it the work of terrorists from Xinjiang. Within 10 hours of the crash, the authorities said they had arrested five suspects in a night raid who were in possession of long knives and flags calling for "jihad".
5. How have Uighurs responded to these attacks?
While some Uighur leaders have condemned such recent attacks, they have done so at times with caveats.
"There is no legitimate reason to attack civilians. We express our condolences to the family members of the dead," said Dilshat Rexit after the Kunming incident, a spokesman for the exile group World Uighur Congress. But he added: "China has to deal with the incident transparently; it cannot serve as a new political excuse for further clamping down on Uighurs, serious discrimination and repressing policies... I urge China (to) stop the current discriminative policies immediately."
After the Tiananmen Square crash, Uighur leader Rebiya Kadeer (above) issued this statement as president of the World Uighur Congress: "The Chinese government will not hesitate to concoct a version of the incident in Beijing, so as to further impose repressive measures on the Uighur people."
Critics also accuse the Chinese government of using the threat of separatists to justify their heavy-handed security and policies in Xinjiang and fear the most recent incidents will only result in even worse crackdowns and backlash as a result.
Source: Washington Post, CNN
Key flare-ups since 2009
July 5: Hundreds, perhaps thousands, of Uighurs riot in the Xinjiang capital Urumqi after security forces move in on a protest over the death of two Uighurs in a brawl with Han Chinese. Nearly 200 people are killed in the unrest, with more than 1,600 injured and hundreds arrested.
Sept 2: Han Chinese residents in Urumqi protest for days over a wave of syringe stabbings which the government blames on "ethnic separatist forces". Nearly 500 people are hurt in the attacks.
July 18: Police kill 20 protesters in clashes in Hotan, southern Xinjiang, according to exiled Uighur groups. State media says police fire on demonstrators who attacked a police station.
July 31 to Aug 1: Two attacks by alleged terrorists leave 13 dead in a Han Chinese section of Kashgar. Police kill eight suspected Uighur separatists.
Feb 28: Rioters armed with knives kill at least 10 people in Yecheng city, Xinjiang, while police kill two attackers, say state media reports. One man is later sentenced to death.
April 23: Gunfights in Xinjiang's Bachu county leave 15 policemen and community workers and six terrorists dead. Two men are later sentenced to death.
June 26: At least 35 people are killed when, according to Xinhua, "knife-wielding mobs" attack police stations and other sites in Lukqun before security personnel open fire. Three people are later sentenced to death.
Oct 28: Three members of a family from Xinjiang crash their car into tourists near Tiananmen Square in Beijing, killing two. The trio are also killed in what the authorities call a terrorist attack.
Jan 25: Twelve people are killed in Xinjiang's Xinhe county, six in explosions and another six shot dead by police dealing with "violent incidents", according to a government-run news portal.
Feb 14: Eleven people die in an attack on police in Wushi. Officers shoot and kill eight, while three blow themselves up, the authorities say.
March 1: Knife-wielding assailants, said to be from Xinjiang, kill 29 people at Kunming city's train station
Apr 30: Assailants armed with knives and explosives carry out an attack at a railway station in Urumqi, killing one person and wounding 79. Chinese police blamed it on the East Turkestan Islamic Movement (ETIM).
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