URUMQI, China -- Assailants in two SUVs plowed through shoppers while setting off explosives at a busy street market in China's volatile northwestern region of Xinjiang on Thursday, killing 31 people and injuring more than 90, local officials said.
The attack in the city of Urumqi was the bloodiest in a series of violent incidents over recent months that Chinese authorities have blamed on radical separatists from the country's Muslim Uighur minority. The Xinjiang regional government said in a statement that the early morning attack was "a serious violent terrorist incident of a particularly vile nature."
The two vehicles crashed through barriers at 7:50 a.m. and drove right into the crowds while setting off explosives, the statement said.
The SUVs then crashed head-on and one of them exploded, the official Xinhua News Agency reported. It quoted an eyewitness as saying there were up to a dozen blasts in all and that at one point one of the vehicles stopped because it was blocked by bodies and handcarts.
"I heard four or five explosions. I was very scared. I saw three or four people lying on the ground," Fang Shaoying, the owner of a small supermarket near the scene of the attack, told The Associated Press by phone.
Photos from the scene posted to popular Chinese social media site Weibo showed at least three people lying in a street with a large fire in the distance giving off huge plumes of smoke. Others, many of them elderly people who frequent the early-morning market, were sitting in the roadway in shock, with vegetables, boxes and stools strewn around them.
Hours afterward, armed paramilitary police and SWAT units patrolled streets surrounding the scene of the attack on Gongyuan North Street near central People's Park. News photographers and videographers were told not to take pictures and were forced to delete their images.
Paramilitary troops were deployed all along the street, a hub for grocery stores, restaurants and bars, many of which were closed.
However, traffic had resumed and there were no signs of the earlier explosion and fire. Chinese authorities usually attempt to tidy up such scenes and restore normality as quickly as possible.
It was not immediately clear who was responsible for the attack or how many attackers took part. Recent violence has been blamed on extremists seeking to overthrow Chinese rule in the region, which is home to the native Turkic-speaking Uighurs but has seen large inflows from China's ethnic Han majority in recent decades.
Xinhua quoted an unidentified jogger on the scene as saying the vehicles were festooned with white flags emblazoned with Arabic script, suggesting a possible link to Muslim extremism.
The death toll was the highest for violence in Xinjiang since dayslong riots in Urumqi in 2009 between Uighurs and Hans left almost 200 people dead. Thursday's attack also was the bloodiest single act of violence in Xinjiang in recent history.
Urumqi was the scene of a bomb attack at a train station late last month that killed three people, including two attackers, and injured 79. Security in the city has been significantly tightened since that attack, which took place as Chinese President Xi Jinping was visiting the region.
In response to Thursday's attack, Xi pledged to "severely punish terrorists and spare no efforts in maintaining stability," Xinhua reported.
Public Security Minister Guo Shengkun, China's top police official, was dispatched to Urumqi as the head of a team to investigate the incident.
In Beijing, Foreign Ministry spokesman Hong Lei said the incident "lays bare again the anti-human, anti-social and anti-civilization nature of the violent terrorists and deserves the condemnation of the world community and the Chinese people."
"The Chinese government is confident and capable of cracking down on violent terrorists. Their plots will never succeed," Hong said.
Russian President Vladimir Putin, who visited China earlier in the week for an Asian security conference, issued a statement saying he "resolutely condemned the bloody crime." Russia, which also faces violence from Muslim extremists, wishes to strengthen cooperation with Beijing "in fighting all forms of terrorism and extremism," the statement said.
Prior to last month's train station attack, Urumqi had been relatively quiet since the 2009 ethnic riots amid a smothering police presence. The sprawling metropolis's population of more than 3 million people is about three-fourths Han Chinese.
The station attack and other violence have been blamed on Uighur extremists, but information about events in the area, which is about 2,500 kilometers (1,550 miles) west of Beijing, is tightly controlled.
Tensions between Chinese and ethnic Uighurs in Xinjiang have been simmering for years, but recent attacks show an audaciousness and deliberateness that wasn't present before. They are also increasingly going after civilians, rather than the police and government targets of past years.
In an unprecedented incident last year, three Uighurs rammed a vehicle into crowds in a suicide attack near the Forbidden City gate in the heart of Beijing, killing themselves and two tourists.
And in March, 29 people were slashed and stabbed to death at a train station in the southern city of Yunnan. The attack was blamed on Uighur extremists bent on waging jihad.
Uighur activists say the violence is being fueled by restrictive and discriminatory policies and practices directed at Uighurs and a sense that the benefits of economic growth have largely accrued to Chinese migrants while excluding Uighurs. The knowledge that Muslims elsewhere are rising up against their governments also seems to be contributing to the increased militancy.
Thursday's attack came two days after courts in Xinjiang sentenced 39 people to prison after being convicted of crimes including organizing and leading terrorist groups, inciting ethnic hatred, ethnic discrimination and the illegal manufacturing of guns.
Among those convicted Tuesday was 25-year-old Maimaitiniyazi Aini, who received five years in prison for inciting ethnic hatred and ethnic discrimination for comments he made in six chat groups involving 1,310 people, the Supreme Court said.
In another case, a Uighur man was jailed for 15 years after he preached jihad, or holy war, to his son and another young man, according to the court.