There are no immediate plans to relax the food-safety restrictions on imports of U.S. beef despite a decision by an international body that says some of them are not necessary, the government said Wednesday.

Japan only allows imports of U.S. beef from cattle not more than 20 months old, citing concerns about mad cow disease, which is believed to be more likely to affect older animals. The U.S. is calling for that restriction to be eased.

The World Organization for Animal Health recently said the United States was a "controlled risk nation," a category that means countries can export their beef there irrespective of the animal's age, according to Toshio Katagai, a health ministry official.

The organization's decision was reached at a meeting in Paris to discuss the safety of animal products.

However, Japan, which has so far found mad cow infections only in cows 20 months or older, will not immediately revise its policy on U.S. beef, the government said Wednesday.

"This will not lead to an immediate change of Japan's import conditions," Chief Cabinet Secretary Yasuhisa Shiozaki said. "It is important to respond to this issue by taking concrete steps in line with scientific facts to ensure food safety and consumers' trust."

Japanese officials have been inspecting U.S. meatpackers that export beef to Japan to evaluate their compliance with restrictions Tokyo imposed because of mad cow disease concerns.

Japan banned imports of American beef in December 2003 after the first case of mad cow disease in the U.S. was found.

The ban was eased in December 2005 but tightened again the following month after prohibited spinal bones were found in a U.S. veal shipment. Tokyo eased the restrictions again last July, but allowed only meat from cows 20 months old or younger to enter Japan.