BEIJING: Twenty-one people, including police officers and social workers, were killed in violent clashes in China's ethnically-divided western region of Xinjiang, a local official said Wednesday.

“Twenty-one persons were killed in all ... including social workers and policemen,” an official surnamed Cao from the provincial government's news office said of the incident, which, he added, occurred on Tuesday.

Gun fights broke out in Bachu county in the west of the province after police went to search the home of locals suspected of possessing guns, a report on Tianshan Net, a government-run news website, said.

It said 15 of those killed were either police or social workers, with 11 of them being members of China's Uighur ethnic minority, who live mainly in Xinjiang and are mostly Muslim.

A further six “gang members” were shot dead in the violence, while eight more were arrested, the report said, without giving their identities. The local official, Cao, identified them as Uighurs.

The report said an investigation showed that the gang members had been plotting to carry out “terrorist activities”, and branded the fighting a “violent terror incident”.

Xinjiang, a region about twice the size of Turkey, is home to around nine million ethnic Uighurs, many of whom complain of religiousand cultural repression by Chinese authorities. The region is regularly hit by unrest.

Officials and state media blame the unrest on “terrorists” but some experts say the government has produced little evidence of an organised terrorist threat, adding the violence stems more from long-standing local resentment.

China has repeatedly accused ethnic Uighurs of carrying out terrorist activities in the province, where 20 men were jailed in March on terrorism charges, which a Uighur rights group branded “repressive.”Riots between Uighurs and members of China's Han ethnic majority in Xinjiang's capital Urumqi in 2009 killed around 200 people, leading the ruling Communist Party to tighten surveillance and boost investment in the region.

The province saw more than half of China's “endangering state security”trials last year, but is home to less than two per cent of the country's population, suggesting “ethnic discrimination”, the Dui Hua Foundation advocacy group said.

According to official figures, 46 per cent of Xinjiang's population is Uighur, while another 39 per cent are Han Chinese, after millions moved to the area in recent decades.