TOKYO (AP) _ Japan will take action if the United States imposes sanctions on Tokyo for expanding its whaling program, the government's top spokesman said Wednesday.

``If the U.S. does in fact impose sanctions on us unilaterally, we would have to take action in line with international rules,'' Chief Cabinet Secretary Hidenao Nakagawa said.

While Nakagawa did not elaborate, Japan's response could include lodging a complaint with the World Trade Organization, Kyodo News Agency quoted an unidentified Japanese official as saying.

U.S. Commerce Department officials said last week they were considering asking President Clinton to ban imports of Japanese fishery products. A ban would show opposition to Japan's decision to add larger Bryde's and sperm whales to its research program, which previously was confined to minke whales.

The International Whaling Commission banned commercial whaling in the mid-1980s but allowed whaling countries to kill whales to gather information on migration, eating patterns and pollution levels. Japanese officials claim that there is no way to conduct the research without killing whales.