By James Pomfret and Michael Martina
KUNMING/BEIJING (Reuters) - Police swept a Uighur district of China's southwestern city of Kunming hours after knife-wielding assailants killed 29 people in a crowded station, bloodily underscoring the risk of ethnic tensions spilling over the borders of restive Xinjiang region.
China has vowed to crack down on what it said were extremist groups who want to transform Xinjiang into an independent state called East Turkestan, but also sought to emphasize ethnic unity in the wake of what it described as a terrorist attack.
Xinjiang, in China's far west, is home to the Muslim Uighur people, many of whom say they chafe at Chinese restrictions on their culture and religion.
In Kunming, the capital of Yunnan province hundreds of miles southeast of Xinjiang, members of the small Uighur community spoken to by Reuters said the situation was tense.
"I alone have already been checked three times. The police point their guns at us. We don't know what really happened either," Uighur restaurant worker Aniwar Wuppur told Reuters.
Residents in Kunming's Dashuyin district, where many Uighurs live, said police came through the neighborhood hours after the attack, rounding up dozens of people for questioning.
Several Uighur men said they were not physically harmed, but had been interrogated for hours.
One family from Xinjiang, grilling skewers of mutton over charcoal at a streetside stall, said police had stormed into their home, pointing guns at their faces.
"It's very tense now. You can feel it," said the 24-year-old man running the stall, who declined to be named. "Even though people don't say or do anything, they're staring at us all the time."
DANGERS OF EXTREMISM
Saturday's violence was the first major attack blamed on people from Xinjiang so far from the region since an incident in Beijing's Tiananmen Square in October, when a car ploughed into tourists killing the three people inside and two bystanders.
Before these two incidents, violence had largely been confined to Xinjiang, a region that borders ex-Soviet Central Asia, Afghanistan, Pakistan and India, where more than 100 people have been killed in the past year.
Chinese media have criticized foreign news organizations for their coverage of the attack, saying they glossed over the dangers of extremism in China by instead faulting Beijing's policies for spurring dissent. Beijing says Uighurs are granted wide religious, cultural and linguistic freedoms.
With the brutal imagery of slashed victims circulated on the Internet, high death toll and geographic separation from Xinjiang, the Kunming attack will provide a ready example for Chinese leaders who stress the growing threat they say China faces.
Experts say extremist ideology does in part fuel the violence, but the level of organization has long been disputed.
"It certainly is the case that there is continued dispute of what exactly is the nature of the physical or armed conflict between separatist forces and the Chinese state," said Barry Sautman, a political scientist at the Hong Kong University of Science & Technology.
"This may change some minds about the existence of terrorist organizations in China."
Chinese state television said that a female suspect was wounded and captured in the attack and that another woman was among suspects being sought. Four attackers were shot dead.
"My impression is that ethnic polarization is the driver behind this, not only religion," said Nicholas Bequelin, a senior researcher at Human Rights Watch.
"Religion is the vehicle, the ready-made ideology that allows some people to embark on plans that are inhuman and brutal."
"SEND THEM ALL BACK"
Zhu Weiqun, chairman of the ethnic and religious affairs committee of the top advisory body to parliament, which meets this week in Beijing, told the website of the Communist Party mouthpiece, the People's Daily, that such violence should not be linked to specific ethnic groups.
"If we end up taking our anger about this incident out on a particular ethnic group and equate one ethnic group with violent terrorism then that is completely incorrect, this is exactly what the separatists want," Zhu said.
There have been no signs of reprisals against Uighurs in Kunming, but some Han Chinese residents voiced their anger.
"They should just send them all back, and not let them come to Kunming anymore," said Yang Jing at her sewing shop across the street from a Uighur restaurant. "They're hateful. Even their small children steal things and fight, and the adults are even worse."
Others said the attack had left a psychological scar.
"You can't blame all Xinjiang people for this," said Li Baochang, passing through the Dashuyin district. "But suspicions are growing and sometimes, even if we don't want to, the feelings in our hearts have changed."
(Additional reporting by Maxim Duncan in KUNMING and Megha Rajagopalan in BEIJING; Editing by Alex Richardson)