The death toll after riots in China's far western region of Xinjiang has risen from 27 to 35, state media say.

The rioters had attacked police stations with knives and set fire to police cars on Wednesday, killing 24 people, reports said.

The police killed 11 of the attackers and captured four, the report added.

There are sporadic outbreaks of violence in Xinjiang, where there are ethnic tensions between Muslim Uighur and Han Chinese communities.

State media have described the incident as a "terrorist attack", but provided no information about the ethnicity of the rioters or what sparked the incident.

At the scene When we approached the town of Lukqun we hit a checkpoint. The area was swarming with armed police. Nobody - including us - was getting through. Locals have been warned not to speak out. We were followed for the whole day by officials in a black car. There has yet to be any official explanation as to what triggered the violence. But some locals told us it was caused by a religious dispute. It has echoes of a similar incident in Xinjiang this April in which more than twenty died. Beijing blamed the violence on terrorists. But locals told the BBC that the incident was triggered after officials prevented women from one devout Muslim family from wearing full veils. It was claimed they pressured the men to shave their beards. What is clear from recent events is the smouldering tensions that exist on China's rugged western frontier.

Confirming reports from the region is difficult because information is tightly controlled.

The violence occurred in Turpan's remote township of Lukqun, about 200km (120 miles) south-east of the region's capital, Urumqi, early on Wednesday.

Sixteen of those killed by the rioters were from the Uighur ethnic group, state-run news agency Xinhua said.

Two police officers were amongst the victims, Xinhua added.

Security has been stepped up, with foreign journalists being denied access to Lukqun town.

Uighurs make up about 45% of Xinjiang's population, but say an influx of Han Chinese residents has marginalised their traditional culture.

Beijing authorities often blame violent incidents in Xinjiang on Uighur extremists seeking autonomy for the region. Uighur activists, meanwhile, accuse Beijing of over-exaggerating the threat to justify heavy-handed rule.

In 2009 almost 200 people - mostly Han Chinese - were killed after deadly rioting erupted in Urumqi between the Han Chinese and Uighur communities.