The city of Kashgar in western China in the region of Xinjiang is under curfew after further outbreaks of ethnic trouble there.
At least 100 people have reportedly been detained and 15 people died.
The BBC reports the trouble began on Saturday when two men killed a truck driver, then drove his lorry into pedestrians and attacked them with knives, killing six. One of attackers was also killed.
In addition, the Xinhua news agency says an explosion on Sunday killed three people and police shot dead four ''suspects''.
Xinjiang has a Muslim Uighur minority and has seen serious ethnic tension.
Xinhua said the truck incident was preceded by two explosions. Twenty eight people were reported to have been taken to hospital.
Another explosion occurred on Sunday, which Xinhua said killed three people.
The BBC reports this was the second outbreak of trouble in Xinjiang in July.
Several police officials and a number of civilians were killed in an attack on a police station in the city of Hotan on 18 July.
Nearly 200 people died after tensions flared between the Uighurs and the Han during riots in Xinjiang in 2009.