BEIJING - China says it's investigating U.S. claims that a Chinese company exported contaminated wheat gluten implicated in pet deaths in North America.

A Chinese official says today that sampling and examination of wheat gluten are underway nationwide and will focus on melamine.

The chemical used to make plastic and as fertilizer in Asia was identified by the U.S. Food and Drug Administration as the contaminant in wheat gluten imported by a U.S. company and used in pet food that was recalled last month.

At least six companies in Canada and the U.S. have recalled more than 100 brands of pet foods and treats made with the contaminated ingredient.

One of them, Ontario-based Menu Foods, has confirmed 16 pet deaths and is the target of at least seven class-action lawsuits.

But anecdotal reports suggest hundreds of cats and dogs may have died of kidney failure.

China also clarifies a newspaper report that it never exported wheat gluten to the U-S -- now saying it never exported wheat gluten containing the rat poison aminopterin.

That poison was identified by the New York State Food Laboratory as the likely culprit in the tainted pet food, a finding the F-D-A later rejected.

Meanwhile the Chinese exporter says the wheat gluten was bought from companies in neighbouring provinces.

Only 876 tons of the 10-thousand tons of wheat gluten it makes each year were linked to tainted pet food.

That raises the possibility that more of the contaminated product could still be on the market in China or abroad.