Chinese officials say a chemical factory has illegally discharged waste water into a river in southern China, affecting the drinking supply of about 40,000 people.

The official Xinhua news agency says an eight kilometer stretch of the Sancha River in Guangdong province has been tainted by the chemical discharge. It did not specify the type of chemical, but said large quantities of dead fish and poisoned livestock have been reported.

Xinhua said the local government has ordered waterworks companies and residents to avoid using the river for its water supply, particularly in the town of Changqi. The name of the chemical company responsible for the spill was not available.