Lt. Gen. Edward Rice, before he steps down next week as the commander of U.S. Forces Japan, said Thursday it is natural for any country, including Japan and China, to face bilateral "challenges" and expressed optimism the two countries will be able to move forward in a positive direction.

Japan-China relations have been severely strained over the arrest of a trawler captain last month near the uninhabited Senkaku Islands in the East China Sea. The islets are controlled by Japan but are claimed by China and Taiwan and are often the source of diplomatic tension.

During a round-table news conference with media outlets in Minato Ward, Tokyo, the air force officer said there are "no major conflicts" in the region.