Over 470 people have been stabbed with syringes in China's restive Xinjiang region, state-run television reported on Thursday, blamed the incidents for fresh protests in Urumqi city.
"Since August 20, the Xinjiang government has been receiving reports by local disease control centres that people have been attacked with syringes," said a report on Bingtuan Television, a Xinjiang-based station.
It added that 476 people had reported being attacked, but did not say whether the syringes that had been used were empty or contaminated.
Crowds of angry Han Chinese protesters took to the streets of Urumqi on Thursday demanding better security after the attacks, less than two months after ethnic unrest rocked the capital of Xinjiang, leaving nearly 200 dead.
The precise number of demonstrators was not immediately clear. Witnesses described large crowds, with some putting the turnout in the thousands.
"The reason for the protest was because people were stabbed by the needles," a woman who runs a local medical clinic told AFP, asking not to be named.
Bingtuan Television, run by the Xinjiang Production and Construction Corps, a semi-military organisation in China's northwestern region, said police had detained 15 people over the needle stabbings, and four were facing charges.
"Those guilty will be punished severely," the report said, quoting police.
The official Xinhua news agency has said the attackers targeted members of nine ethnic groups, including Han Chinese and Muslim Uighurs, but no one had been infected or poisoned.
The July violence between Han Chinese and Uighurs was the worst ethnic unrest in China for decades.
Many of the roughly eight million Uighurs in Xinjiang complain of decades of Chinese religious, political and cultural repression -- a claim Chinese authorities deny.