Chinese baby formula contaminated with melamine may be for sale in ethnic grocery stores in the U.S., officials with the Food and Drug Administration warned Thursday.

The department urged consumers not to use infant formula from China, where several brands have been tainted with melamine (cyanuramide), a chemical used to make plastics and fertilizers.

There is no immediate word on whether the formula may be on sale in Canada.

All U.S. brands of formula are safe, the FDA said, and no Chinese brands are approved for export to the U.S.

But it's possible that ethnic grocers may be selling formula from China, particularly in cities with large populations of Chinese immigrants.

There are no reports of illnesses in the U.S.

Death of Chinese baby under investigation

Earlier on Thursday, Chinese health officials announced traces of contamination have been found in a brand of baby formula that may have killed one baby in China and sickened others with kidney stones.

Traces of melamine, which can cause kidney stones, were found in Sanlu-brand milk formula, the country's Health Ministry said.

Sanlu, a Chinese dairy company, has recalled formula made before Aug. 6. A spokesperson for Sanlu said the company is investigating whether counterfeit formula was mislabelled.

Doctors in China's northwestern Gansu province said it is rare for babies to develop kidney stones, never mind 14 cases at once, the official Xinhua news agency and China Daily reported.

Since then, cases have emerged at two other hospitals in Gansu, as well six other provinces in central, eastern and northern China, Xinhua said.

One baby with kidney stones has reportedly died, but there is no clear link to the milk powder, the news agency quoted a Gansu provincial Health Department spokesman as saying.

Health officials in Gansu were aware of the potential risks since July 16, Xinhua said. No explanation was given for the delay in disclosure.

Kidney stones are masses of salts or minerals that crystallize in the kidney. If the stones become large enough to stop the flow of urine from the kidney, they need to be removed surgically or by other methods.

In 2004, at least 13 babies in China's eastern Anhui province died after they drank fake formula that investigators said had no nutritional value. The deaths prompted food and health investigations and international concern.

Last year, the former head of China's food and drug administration was executed for taking bribes to approve untested medicine.

Also last year, Canada's food watchdog said it had intercepted a shipment of corn gluten from China that tested positive for melamine. Canadian fish farms and pet foods have also been affected by melamine contamination.

With files from the Associated Press