Japan has no immediate plans to relax its strict conditions on imports of U.S. beef, despite a decision by an international body saying some restrictions were 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. has called 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 beef 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 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."

U.S. Agriculture Secretary Mike Johanns urged countries that import U.S. beef to review their policies after the decision in Paris.

"We will use this international validation to urge our trading partners to reopen export markets to the full spectrum of U.S. cattle and beef products," Johanns said in a statement released Tuesday.

"We are notifying our trading partners of our expectation that they commit to a timeframe to amend import requirements," he said.

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

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

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