URUMQI, China — Saying terrorists will be "hunted down and punished," authorities launched a security crackdown Saturday in China's Muslim northwest, site of a deadly bombing that has the central government in far-off Beijing bracing against violence that some say heralds a rise of organized extremism in the region.
Thursday's bombing at a morning street market selling vegetables and other produce in Urumqi, capital of the Xinjiang region, killed at least 43 people and left the region's ethnic Chinese on edge.
"We don't know why there have been explosions, but we are definitely worried about personal safety," said Luo Guiyou, a member of China's Han ethnic majority who manages an auto parts store.
Police announced names of five people blamed for the attack and said they were part of a "terrorist gang." Based on their names, all appeared to be Uighurs, the region's most populous Muslim minority. Police said that four of the assailants were killed in the bombing and that the fifth was captured Thursday night.
An anti-terrorism campaign with Xinjiang "as the major battlefield" will target religious extremist groups, underground gun workshops and "terrorist training camps," the official Xinhua News Agency said. "Terrorists and extremists will be hunted down and punished."
Beijing blames unrest on extremists with foreign ties, but Uighur activists say tensions are fueled by an influx of migrants from China's dominant Han ethnic group and discriminatory government policies. Thursday's bombing has raised questions about whether Beijing's tightening grip might be feeding anti-China anger and a rise of organized terrorism in the country.
"The violence is an indication that people are willing to take more drastic measures to express their opposition," said David Brophy, a Xinjiang historian at the University of Sydney.
A heavy-handed response might backfire by inciting sympathy from Central Asian radicals about "the plight of Muslims in Xinjiang," said Ahmed A.S. Hashim, a terrorism expert at Singapore's Nanyang Technical University.
"In fact, groups like al-Qaida and others are now beginning to think that China could be a new oppressor of the Muslim world," he said.
In Beijing, police announced that they were canceling vacations for officers and would step up patrols at train stations, schools, hospitals and markets.
A measure under which passengers at stations in central Beijing are required to undergo security checks will be extended to three additional stations, the city government said. Passengers at all stations already are required to submit handbags and parcels for X-ray examination under rules imposed ahead of the 2008 Summer Olympics in Beijing.
Thursday's violence was the deadliest single attack in Xinjiang's recent history, and the latest of several that have targeted civilians in contrast to a past pattern of targeting police and officials. It was the highest death toll since several days of rioting in Urumqi in 2009 between Uighurs and members of China's dominant Han ethnic group left nearly 200 people dead.
On Saturday, paramilitary police with rifles stood every 20 meters (70 feet) along the streets around where the bombing took place. The street where the market was located was closed to vehicle traffic.
Li Shengli, who was in Urumqi on a business trip from Shanghai, brought three stems of yellow chrysanthemums.
"I am here to remember the dead," he said. He was quickly pulled away by an official who warned him not to talk to reporters.
The family of one victim, Lu Xiangwang, a 58-year-old driving teacher, said they were waiting to receive his body.
In his parents' apartment near the market, Lu's mother sat sobbing on a couch, surrounded by relatives. A neighbor, Ji Jinzhu, said Lu spent the night before the attack at the apartment to look after his ill father.
"He was hit by an explosive just moments after he stepped outside this residential compound into the street," Ji said. "The father is feeling very guilty because had it not been for his illness, his son would not have had to come to take care of him."
Ji, 80, said he was shopping in the crowded market Thursday morning with his wife when the two off-road vehicles raced into the street.
"When they passed me, I heard explosions and saw flames going up into the sky and smoke filling up the air," he said.
An Associated Press reporter who visited a Uighur neighborhood was escorted away by 11 uniformed police officers and street wardens.
The influx of ethnic Han Chinese has left Uighurs (pronounced WEE-'gurs) feeling marginalized in their homeland and excluded from decision-making.
Beijing has responded with an overwhelming security presence and additional restrictions on the ability of Uighurs to travel, as well as on their culture and religious practices.
Recent attacks show increased audaciousness and deliberateness. They are aimed at the public instead of police and government targets. But their planning and weapons still are relatively simple, suggesting a lack of foreign support.
"I don't think there's any doubt that these acts qualify as acts of terrorism," said Brophy, the Xinjiang historian. "But there's still very little hard evidence that would allow us to describe a terrorist network or a terrorist organization operating in Xinjiang."
Security was tightened still further after a bomb attack last month at an Urumqi train station as Chinese President Xi Jinping was visiting the region. Three people were killed, including two attackers, and 79 were injured.
Prior to the train station attack, Urumqi had been relatively quiet since the 2009 ethnic riots. The city's population of more than 3 million people is about three-fourths Han Chinese.
In March, 29 people were slashed and stabbed to death at a train station in the southwestern city of Kunming. That attack was blamed on Uighur extremists.
On Friday evening, some major roads in Urumqi were closed while more than 100 army trucks and police vehicles drove down them in a show of force, according to state media.
One banner carried by a vehicle read: "Fighting against violent crime according to law to resolutely safeguard social stability."
Beijing says an organized militancy with elements based overseas is behind the attacks. However, little evidence has been provided to back up the claim and many analysts doubt such an organization exists.
Xinhua, the government news agency, said the group blamed for this week's attack "took part in illegal religious activities, watched and listened to terrorist violence video and audio materials."
Beijing promotes the notion of a "terrorism movement" in Xinjiang to justify heavy security while avoiding foreign criticism and possible damage to relations with Islamic nations, said Hashim, the terrorism expert.
A handful of Uighur activists might be veterans of fighting in Afghanistan, he said.
"They seem to be getting better at what they are doing in terms of causing violence," Hashim said. "But it's still, from my perspective, not the dire threat that China wants to paint it to the outside world."
Watt reported from Beijing.