Petco Animal Supplies Inc. said it has pulled all Chinese-made cat and dog treats from its website and stores nationwide after concerns that the treats had sickened thousands of pets.

Petco said the move made it the first national pet retailer to yank the treats from shelves.

The San Diego-based company and its rival PetSmart vowed in May to remove treats made in China after the U.S. Food and Drug Administration said it had received about 4,800 complaints of pet illnesses that might have been linked to jerky treats made in China.

Phoenix-based PetSmart Inc. will stop selling treats manufactured in China by March, said spokeswoman Erin Gray. The move was announced Monday.

“We believe this is the right thing to do,” said Jim Myers, Petco’s chief executive.

The FDA has been investigating pet illnesses and deaths in animals who ate jerky pet treats since 2007 but has not been able to identify a cause for the illnesses.

In a May update on the issue, the FDA said it had received reports of more than 1,000 dog deaths.

The majority of complaints involve dogs, but cats also have been affected.

The FDA warned pet owners who feed their dogs jerky treats to keep an eye out for decreased appetite and activity, vomiting and diarrhea.