The simmering conflict in China's western province of Xinjiang burst into the open again Wednesday, with state media reporting 27 people died in the latest violence to hit the largely Muslim region.

Though state media gave no explanation of what triggered the bloodshed, pictures posted on a social media account affiliated with the main CCTV station showed smashed vehicles and what appeared to be a partially burned police station in Shanshan County, near the city of Turpan, 250 kilometres east of the regional capital of Urumqi.

A posting on the English-language @cctvnews Twitter account referred to "insurgents" having attacked a police station. However, a correction was quickly issued removing the word "insurgent" – which infers an organized uprising against Chinese rule in Xinjiang – and referring to the violence instead as a "riot."

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The official Xinhua newswire said that 17 people, including nine policemen, were killed by "knife-wielding mobs" Wednesday "before police opened fire and shot dead 10 rioters." Three others were reported injured, and at least three of the assailants were being pursued by police after escaping the scene.

Some reports said Shanshan was under "martial law" late Wednesday, with police openly displaying weapons as they patrolled the streets.

Though Xinhua made no mention of the ethnicity of the attackers, many among Xinjiang's native Uighur population are deeply resentful of Beijing's heavy-handed rule over the vast province – Xinjiang is triple the size of France – and its efforts to spread Han Chinese culture and population through the region.

The situation was very tense when The Globe and Mail visited Urumqi earlier this month. The police station near the city's main mosque and bazaar was guarded by a unit of riot cops who were deployed into the street outside with shields raised and assault rifles visibly ready.

Outside the city, a squad of Chinese special forces troops conducted drills beside a highway tollbooth, their training and ferocity put right in front of each car as it pulled to a mandatory stop.

Twenty-one people were killed in April in what state media called a "terrorist" attack that also included an assault on a police station near the southern city of Kashgar, near Xinjiang's narrow frontiers with Afghanistan and Pakistan.

However, locals say that attack was provoked by police who tried to force a family of Muslim women to stop wearing head-to-toe niqab coverings, and the men of the family to shave their beards. Though beards and loosely worn headscarves are common in Urumqi, Uighurs in rural areas of Xinjiang complain of pressure to act and dress in secular fashion.

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Decades of government policies – including preferential access to government jobs and farmland – aimed at encouraging Han migration to the region have drastically reshaped the demographics of Xinjiang. A 2011 census revealed that 40 per cent of the province's 22 million residents are now Han Chinese, up from less than 7 per cent in the 1950s.

Wednesday's attack comes ahead of the fourth anniversary of a deadly outbreak of fighting between rival mobs of Han Chinese and Uighurs in Urumqi that left almost 200 people dead.