A top Chinese official said Thursday 15 people have been arrested over a factory brawl that left two Muslim Uighur men dead and was a crucial trigger for deadly unrest in the Xinjiang region.

Among those arrested were those believed to have killed the two Uighur workers, according to Wang Yang, the Communist Party secretary in southern Guangdong province, where the factory fight erupted.

"For now the interpretation of this accident is that it was a conflict between employees and it will be regarded as a single crime and will be subject to judicial process," he told reporters.

"The investigation of the case is progressing smoothly."

The brawl erupted between Uighur and Han Chinese workers at a Hong Kong-owned toy factory late last month over Internet rumours about an alleged rape.

A protest by the Uighur community against the factory violence in Xinjiang's capital Urumqi on July 5 descended into violence, with at least 197 people dead, according to the government.

Exiled Uighur activist Rebiya Kadeer however said in Tokyo on Wednesday that nearly 10,000 people had "disappeared in one night" after the violent clashes -- the worst ethnic violence in China in decades.

The claim was dismissed by a Xinjiang government spokeswoman in a report Thursday in the state media.