NEW YORK (AP) — Petco said Tuesday that it will stop selling dog and cat treats made in China by the end of this year due to ongoing fears that the imported treats are making pets sick. 

The U.S. Food and Drug Administration hasn’t been able to figure out why pets are getting ill. Since it launched an investigation late last year, the FDA said it received more than 4,800 complaints of pet illnesses and 1,000 reports of dog death after eating Chinese-made chicken, duck or sweet potato jerky treats. Last week, the FDA said tests found antiviral drug amantadine in some samples of imported chicken jerky treats sold a year or more ago, but doesn’t think it caused the illnesses. The FDA said it will continue to investigate.  

Petco said that shoppers have asked the pet food retailer to stop selling treats from China. Petco said it is switching them out for treats that are made in the U.S., New Zealand, Australia and South America. It started cutting down on the amount of treats it sold from China about three years ago, said Petco Vice President John Sturm. It doesn’t sell any pet food made in China. 

Petco, which is based in San Diego, runs 1,300 stores around the country. 

Rival PetSmart Inc., which is based in Phoenix and runs about 1,300 stores, didn’t immediately respond to a request for comment.