WASHINGTON — Tainted infant formula from China may be on sale at ethnic groceries in this country, even though it is not approved for importation, federal officials warned yesterday.

However, the Food and Drug Administration stressed that the domestic supply of infant formula is safe.

FDA officials are urging American consumers to avoid all infant formula from China, after several brands sold in that country came under suspicion of being contaminated with melamine, a chemical used in plastics. Officials said there have been reports from China of babies developing kidney stones as a result. There have been no reports of illnesses in America.

“We’re concerned that there may be some infant formula that may have gotten into the United States illegally and may be on the ethnic market,” a deputy director of the FDA’s food safety program, Janice Oliver, said. “No infant formula from China should be entering the United States, but in the past we have found it on at least one occasion.”

After hearing of the latest food safety scandal in China, the FDA checked with formula manufacturers who have approval to market here. But none receive formula or ingredients from China. Formula manufacturers get close scrutiny from the government. They are required to register with the FDA and comply with specific nutritional standards.