The European Union says it is preparing measures to ensure that genetically modified rice from the United States does not enter European markets.

An EU spokeswoman says the measures should be released on Wednesday, less than a week after traces of the modified rice were found in some U.S. supplies.

The U.S. Department of Agriculture says it is studying how the unauthorized rice entered the food supply, but it says the modified product should pose no risk to humans or the environment.

Officials say the maker of the rice announced plans to seek approval for its sale, after the modified strain was discovered on the market.

Japan's government has placed a ban on U.S. imports of long-grain, because of the incident.

Some information for this report was provided by AFP and AP.