URUMQI, China (REUTERS) - A bombing in western China, which killed three people and wounded 79 on Wednesday, has raised concerns about the apparent sophistication and daring of the attack, possibly timed to coincide with a visit to the heavily Muslim region by President Xi Jinping.
Unidentified assailants used explosives and knives in their attack on a railway station in Urumqi, the first bomb attack on the capital of Xinjiang province in 17 years, at a time of likely heavy security and soon after the arrival of a train from a mainly Han Chinese province, state media said.
On Thursday, dozens of black police vans were parked around the station while camouflaged police with assault rifles patrolled around its entrance. Despite the security, the station was bustling and appeared to be operating normally.
The government blamed the attack on "terrorists", a term it uses to describe Islamist militants and separatists in Xinjiang who have waged a sometimes violent campaign for an independent East Turkestan state - a campaign that has stirred fears that jihadist groups could become active in western China.
Initial accounts of the attack came almost exclusively from Chinese state media, which did not say if any of the attackers had been killed or captured. Nor did they say if President Xi, who was wrapping up his visit, was anywhere near Urumqi at the time.
Pan Zhiping, a retired expert on Central Asia at Xinjiang's Academy of Social Science, described the attack as very well organised, saying it was timed to coincide with Mr Xi's visit.
"It is very clear that they are challenging the Chinese government," he said. "There was a time last year when they were targeting the public security bureau, the police stations and the troops. Now it's indiscriminate - terrorist activities are conducted in places where people gather the most," he added.
The attack was the first bombing in Urumqi since men planted bombs in buses in 1997, killing nine people.
It was also the largest militant attack there since Uighurs - a Muslim community ethnic to western China - stabbed hundreds of Han Chinese with needles in 2009. No one was killed in that incident but it led to protests demanding the ouster of the region's top official for failing to protect Han people, China's majority ethnic group.
"Knife-wielding mobs" slashed at people at an exit of the South Railway Station of Urumqi on Wednesday night and set off explosives, Xinhua news agency said, quoting police. Security is normally very tight at the entrances of railway stations, but exits are often unguarded and crowded.
There has been no claim of responsibility for the attack.
Debris was strewn on the ground after the explosion, though iron rails were left standing, according to images shown by state broadcaster CCTV. Paramilitary officers with rifles guarded the station, with several ambulances parked nearby.
The attack came on the eve of a two-day Labour Day holiday, a time of heavy travel in China, and just as Han passengers were likely to be disembarking from a train from Chengdu, capital of southwestern Sichuan province, Xinhua said.
Mr Pan said the attack could also bolster a more hardline effort by the government to fight terrorism. "It appears that our intelligence work is still not up to speed," he said. "But it's difficult in these circumstances. They are working in the dark and it'll be hard to completely eliminate."
Exiles and many human rights groups say the cause of unrest in the resource-rich and strategically located region is heavy-handed rule by authorities, including curbs on Islam and the culture and language of its Uighur people.
Xinhua said in a commentary that "instigators might be away from the home field", condemning the spokesman for the German-based World Uyghur Congress exile group for saying that"such incidents could happen again at any time".
Wednesday's attack follows a recent spate of attacks blamed by the government on Uighur militants.
In early March, militants stabbed 29 people to death in the southwestern city of Kunming. Five months earlier, a car ploughed into tourists on the edge of Beijing's Tiananmen Square, killing the car's three occupants and two bystanders.
Unrest in Xinjiang has caused the deaths of more than 100 people in the past year, prompting a tougher stance against Turkic-language speaking Uighurs, many of whom resent government controls on their culture and religion.
"The more savage the terrorists, the more resolute the will of the people to safeguard social stability and the more unshakeable the will of all the ethnicities for ethnic unity,"the People's Daily, the official newspaper of the ruling Chinese Communist Party, said in a commentary on Thursday.