Chinese state media say 27 people were killed during rioting in the ethnically-mixed western region of Xinjiang, the worst violence in the area in four years.
The official Xinhua news agency said the riot began early Wednesday when "knife-wielding mobs" attacked police stations, a local government building, and a construction site in the Lukqun township of Shanshan County.
The report said the rioters stabbed people and set fire to police cars, killing nine security personnel and eight civilians before police opened fire and killed 10 assailants. It said police also captured three rioters and are searching for an unknown number of others.
It gave no information on what led to the riots and did not comment on the ethnicity of those involved.
Xinjiang has experienced years of occasional fighting between members of China's mostly Muslim Uighur minority and the Han Chinese majority. Many Uighurs blame Xinjiang's violence on religious and cultural discrimination resulting from a massive influx of Han.
Dolkun Isa, secretary of the World Uighur Congress, told VOA it is difficult to confirm what exactly happened in Wednesday's unrest because of a heavy police presence and what he called an atmosphere of "martial law" prevailing in the area.
But Isa said it was possible that a Uighur mob raided the police station, saying such attacks happen out of a desire for revenge.
"Of course, people get the feelings of revenge, because the police always are restricting the daily lives of people," he said. "They don't allow space for normal life for them. Because Chinese police and the Chinese government are always interrupting their daily lives. They have no space."
A Shanshan County resident told VOA's sister network Radio Free Asia that after the riot, police restricted access to Lukqun, which he described as a small and predominantly Uighur town with only one large road and surrounded by farm land.
The man, who asked not to be identified, said residents usually engage in protests if they believe their grievances have not been properly addressed by Chinese authorities.
"The [Uighur] people in the rural area of this region are normally peaceful and honest, and they don't harbor hatred. If they have hatred, it is because some educated fellows have encouraged them in that way," he said.
China has said it grants Uighurs wide-ranging freedoms, but insisted that it faces a growing threat from terrorists or extremists in the Uighur community who want to form a separate state called East Turkestan.
Exiled Uighur activists such as Isa have disputed those claims, saying China is exaggerating the extremist threat to justify its security clampdown and monitoring of Islamic institutions in Xinjiang.
Wednesday's unrest was the deadliest in Xinjiang since 2009, when more than 200 people were killed in riots that saw the Turkic-speaking Uighurs fight against state security forces and Han Chinese residents.
In April this year, a confrontation between locals and police in the heavily Uighur area of Kashgar killed 21 people.