Japan and the United States are preparing to hold a joint exercise in December that will focus on defending islands in remote waters, sources involved in bilateral relations said Sunday.

The scenario for the exercise is likely to involve an invasion of remote Japanese islands by an armed force, which will give the Self-Defense Forces and the U.S. military a chance to use joint tactics to deal with the situation, the sources said.

The maritime part of the drill is likely to be held on the Pacific side of the Nansei Islands, which consists of such isles as Okinawa and Ishigaki Island. The candidate site for the ground part of the exercise is likely to be the Ground Self-Defense Force's Hijudai exercise area in Oita Prefecture on Kyushu, the sources said.

The U.S. Navy's 7th Fleet is likely to dispatch the aircraft carrier USS George Washington for the sea drill, while the GSDF's Western Army is likely to be dispatched for the ground drill, they said.

The plan, which was drawn up in the previous fiscal year, is not a response to the collisions last month between a Chinese trawler and Japan Coast Guard cutters near disputed territories in the East China Sea, the sources said.

But the exercise will likely highlight the close cooperation between the security allies, given China's strong reaction to the incident, which took place near the Japanese-administered Senkaku Islands also claimed by Taiwan and China.

There is also an exercise planned off the Noto Peninsula in the Sea of Japan to deal with a hypothetical missile attack from North Korea, they said.