Beijing  - Three people were sentenced to up to 15 years in prison Saturday over a series of syringe attacks in Urumqi, the capital of China's troubled western Xinjiang region, state media reported.

In the first case, a 19-year-old identified as Yilipan Yilihamu was sentenced to 15 years for stabbing a woman with syringe on August 28, the official Xinhua news agency reported.

In the second, Muhutaerjiang Turdi, 34, and Aimannisha Guli, a 22-year-old woman, were sentenced to 10 years and seven years in jail respectively for threatening a taxi driver with a syringe and robbing him of 710 yuan (100 dollars).

The report provided no further details about the cases.

Since bloody ethnic riots in July which left at least 197 people dead, Urumqi has been plagued by tensions between its ethnic Uighur and Han Chinese residents.

Last month, reports began appearing of attacks by Uighurs using hypodermic syringes.

The regional government said city hospitals had dealt with 531 victims of needle stabbings, most of them Han Chinese, with 106 people showing "obvious signs" of needle attacks.

The syringe attacks led to a mass protest by mainly Han Chinese, calling on the municipal and regional governments to step up security in the city.

Last weekend, Urumqi Communist Party secretary Li Zhi and Xinjiang police chief Liu Yaohua were removed from their posts.

The government said the syringe attacks were instigated by ethnic separatists, but the Xinhua report about the two cases did not say they were ethnically motivated. (dpa)