At least four people were killed and eight others were injured in a knife attack in central Xinjiang yesterday, according to witnesses and a spokeswoman for the restive autonomous region. Police in Korla arrested one suspect involved in the attack, Xinjiang's publicity chief, Hou Hanmin , told the South China Morning Post , but she failed to confirm the identities of the suspect and victims. She confirmed the casualty count and said the attack took place around 3pm when a man wielding a small knife "attacked people in downtown Korla". She did not know whether the suspect was an ethnic Uygur or Han, as she had been preoccupied in Beijing while accompanying Xinjiang's party chief, Zhang Chunxian, at the National Party Congress. Several pictures of the scene, taken by different witnesses, appeared on Tencent. A motionless man was shown lying on the ground, with several wooden rods around him, while another image showed a woman who appeared to be covered in her own blood. A witness wrote on a Tencent microblog that in the attack in Korla's Jinsanjiao shopping district, a man attacked a female shopkeeper after a quarrel A witness wrote on a Tencent microblog that in the attack in Korla's Jinsanjiao shopping district, a man attacked a female shopkeeper after a quarrel. Another witness said three girls at a shop were attacked with the knife, and the suspect was "beaten to death" by angry onlookers with long wooden rods. But the information posted on microblogs could neither be confirmed nor the identity or ethnicities of the suspect or victims. Many of the pictures and messages had been deleted within an hour after they were posted. Ethnic tensions between Han and Uygur people have been the key reason behind social unrest in Xinjiang in the past few years.