Akira Amari, the minister for the Trans-Pacific Partnership free trade negotiations, told U.S. Treasury Secretary Jack Lew on Tuesday that Washington needs to recognize the importance to Tokyo of retaining tariffs on key agricultural products.

Amari told reporters he explained to Lew in their meeting in Tokyo that protecting certain key products, including rice, from an inflow of cheap foreign products has been "a critical issue" in Japan, but the U.S. "does not seem to be fully aware of that."

Amari added that Prime Minister Shinzo Abe's administration has been facing difficulties in dealing with this issue amid the domestic agriculture industry's fierce opposition to concessions on sensitive products.