China's Xinhua news agency reports at least 11 people have been killed in violence since July 30 in western China's Xinjiang Autonomous Uyghur Region.
Xinhua said police shot dead four suspects in the city of Kashi (also called Kashgar) on July 31 and were searching for four other suspects.
On July 30, two men hijacked a truck in Kashi, according to Xinhua, "stabbing the driver to death and ramming into pedestrians."
The two men then "jumped out of the truck and hacked bystanders."
At least seven people were killed and 11 injured.
The violence in Kashi follows an attack on a police station in Hotan, some 500 kilometers southeast of Kashi, on July 18 that left 18 people dead, 14 of them reportedly "rioters who attacked" the police station.
Xinjiang is the traditional home of the Uyghurs, a Turkic Muslim group.
Clashes between Uyghurs and ethnic Han Chinese, who have been moving to Xinjiang in large numbers as the oil industry there develops, have become more frequent with violence in 2009 leaving almost 200 people dead.
compiled from agency reports