Japan is considering expanding an Okinawa-based ground force unit to defend remote southwestern islands and prepare for a contingency involving Taiwan in the face of China's increasing assertiveness, a government source said Saturday.Upgrading the brigade's highest rank to general is intended to strengthen cooperation between Japan and the United States, as the title would be equivalent to commanding general of the U.S. Marine Corps' III Marine Expeditionary Force, also based in Okinawa.The Defense Ministry has continued to reinforce the Self-Defense Forces in Okinawa in light of China's maritime expansion activities, including repeatedly sending vessels around the Senkakus in an attempt to undermine Japan's control of the uninhabited islets.Following a trip to Taipei by U.S. House of Representatives Speaker Nancy Pelosi in August, the Chinese military held massive exercises around the self-ruled democratic island including the launch of ballistic missiles, five of which fell into Japan's exclusive economic zone in the East China Sea for the first time.Related coverage:Japan ruling bloc agrees on acquiring "counterstrike capability"Japan mulls buying up to 500 U.S. Tomahawk missiles until FY 2027Kishida orders funds to raise Japan's defense budget to 2% of GDP"