A group of knife-wielding assailants burst into a train station in the south-western Chinese city of Kunming late Saturday night, slashing to death at least 29 people and injuring more than 140 others.
The Chinese government has labelled the incident a "premeditated violent terrorist attack" and blamed it on separatists from north-western China's restive Xinjiang region.
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 Saturday night's mass knifing, 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, authorities declared it the work of terrorists from Xinjiang, and within 10 hours of the crash, 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 on Sunday, 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 worse 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.
A survivor of the Kunming railway slashing attack recounts her ordeal to The Straits Times.
Defiant residents of the Chinese city that saw a mass stabbing queued to give blood on Monday, while others vented their anger at what authorities say was a terrorist attack staged by separatists from far-off Xinjiang.
Chinese Internet users on Monday accused the United States of double standards after Washington condemned a deadly knife attack in south-west China but refrained from calling it a terrorist incident.
President Xi Jinping has ordered a major security crackdown to nab those behind Saturday's bloody attack - blamed on Xinjiang separatists - that left 29 civilians dead and more than 140 others injured at a railway station in south-western Kunming city.
China on Sunday promised tough punishment for knife-wielding attackers who killed dozens in an unprecedented train station rampage, blaming separatists from Xinjiang, as witnesses described a city in shock.
Travel agency owner Chen Yugui, 50, was chatting with friends outside the Kunming Railway Building on Saturday night when he heard a loud commotion from the train station located in an adjacent building.
Beijing is vowing to strike back against an unprecedented mass killing of civilians by alleged Xinjiang militants far outside their homeland, but analysts say that may merely speed up the cycle of repression and violent reprisal.
Witnesses to chilling violence at a Chinese train station placed under heavy security on Sunday recalled moments of fear and chaos after at least 29 people were killed in what authorities called a terrorist attack by Xinjiang militants.
The brazen knife attack in south-western Kunming is deliberately timed just before China's political season kicks off, observers say.
China blamed militants from the restive far western region of Xinjiang on Sunday for an attack at a train station on the other side of the country by knife-wielding "terrorists" in which at least 33 died, including four of the assailants, who were shot dead.