A Chinese company accused of selling chemically contaminated wheat gluten linked to pet food deaths of cats and dogs in the U.S. said Thursday it sells most of its wheat gluten within China, raising health concerns over people and animals in China.

That fears are that people or animals in China may have been exposed to tainted wheat gluten, a protein source used as an ingredient in pet food. Beijing authorities have yet to say whether they are investigating.

The U.S. Food and Drug Administration last week blocked wheat gluten imports from the Xuzhou Anying Biologic Technology Development Co. in the eastern city of Xuzhou, saying they contained melamine, a chemical found in plastics and pesticides.

The company has said it is investigating the claims.

Xuzhou Anying produces and exports more than 10,000 tons of wheat gluten a year, according to its Web site. But only 873 tons have been linked to tainted U.S. pet food, raising the possibility that more of the contaminated product could still be on the market in China, or abroad.

Li Cui, director of Xuzhou Anying's exports, told The Associated Press on Thursday that the U.S. is the company's only overseas market for wheat gluten. But it wasn't clear if Anying had more than one company in the United States.

Las Vegas-based ChemNutra Inc. has recalled 873 tons of gluten that it shipped to three pet food makers and a single distributor who supplies the pet food industry.

The company said Tuesday the recall applied only to the product from Xuzhou Anying, one of its three Chinese suppliers of the ingredient. Anying had never reported the presence of melamine in the content analysis it provided, ChemNutra said.

Most of Xuzhou Anying's wheat gluten is sold to domestic Chinese buyers, Li said, refusing to say whether the allegedly contaminated batches were sold in China.

The Chinese Ministry of Health and the Ministry of Agriculture did not immediately respond to questions on whether they had concerns about tainted gluten in China.

China is struggling to improve its food safety record, but manufacturers often mislabel food products or add illegal substances to them.

Last year, seven companies were punished for using banned Sudan dye to color egg yolks red. In 2004, at least 12 infants died from malnutrition after drinking formula with little or no nutritional value in eastern China's Anhui province.

Earlier this week, another official at the Chinese company said the gluten was not manufactured by Xuzhou Anying, but was bought from companies in neighboring provinces.

The FDA has confirmed about 15 pet deaths, and anecdotal reports suggest hundreds of cats and dogs may have died of kidney failure from the tainted food.

Nearly 100 brands of cat and dog food made with wheat gluten have been recalled.

Xuzhou Anying's Web site describes it as a private company set up in 1995 to make and sell animal feed, wheat gluten and vegetables. It said the company produces and exports more than 10,000 tons of wheat gluten each year.