Three people have been killed and more than 20 injured in violence in the city of Urumqi in China's restive Xinjiang region, state media says.
Xinhua news agency said police restored order after demonstrators attacked passers-by and set fire to vehicles. Xinhua did not say how many people were involved or what their motive was.
But activists and eyewitnesses said that those involved in the unrest were minority Muslim Uighurs. An overnight curfew has been declared. Xinjiang is home to about eight million Uighurs, some of whom want independence.
"It started as a few hundred, and then there were easily over 1,000 involved," one unidentified eyewitness told Reuters news agency.