Ethnic unrest among Uyghur residents in China

BEIJING, China (CNN) - Ethnic Uyghur residents in Urumqi, capital of China's far west Xinjiang region, took to the streets Sunday afternoon in a rare public protest that prompted a police lockdown of the city.

China's official Xinhua News Agency said protesters attacked passersby, burned public buses and blocked traffic. The report did not say how many people took part in the protest or what their grievances were.

But a witness in Urumqi told CNN that, soon after the protest started around 5 p.m., "hundreds [of protesters] grew into easily over a thousand - men, women and children, all ethnic Uyghurs, screaming and chanting."

Local police arrived quickly and tried to control the swelling crowd by erecting barriers in the street, but "people pushed them over," the witness said. "They were throwing rocks at passing cars and buses." As the violence escalated, hundreds of anti-riot police arrived on the scene, the witness said.

"They used tear gas and fire hoses to disperse the crowd. I saw fire trucks, ambulances, armed personnel carriers, and what looked like tanks. I heard random gunshots."