China Xinjiang tensions
Policemen in riot gear guard a checkpoint on a road near a courthouse where ethnic Uighur academic Ilham Tohti's trial is taking place in Urumqi, Xinjiang Uighur Autonomous RegionReuters

Chinese authorities have said the recent violence in the restive Xinjiang region killed at least 50 people.

Police had earlier put the death toll at just two after a series of blasts rocked Luntai county.

According to the state-run news agency Xinhua, 40 rioters, six civilians and four policemen were killed in the incident. The report did not specify how the people were killed.

Local reports say some of the "rioters" were shot dead by police officers after they attempted to blow themselves up; two others were captured.

The Xinjiang police blamed separatists for the attack and said the blasts were an "organised and serious" terrorist attack.

The main suspect, Mamat Tursun, who was alleged to be an active extremist by the police, was also reportedly shot dead in the attack.

One of the three bombs went off in a busy shopping area of Luntai, which is located about 360kms southwest of the capital Urumqi.

The explosions came a few hours after 17 local government officials in Kashgar prefecture were punished for alleged dereliction of duty.

Officials, including police officers, were penalised for alleged negligence in the July attack, which claimed the lives of more than 100 people.

Tensions have remained high in the volatile Xinjiang region as the federal administration blames Uighur separatists, who want an independent state, for the rise in violence.

Rights activists and the Uighur rebels, however, blame Beijing's tightening grip.