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 close to the matter said on Saturday. In a move that could further heighten tensions with China, the Defence Ministry plans to increase the number of infantry regiments under the Ground Self-Defence Force’s 15th brigade to two, as well as upgrade its highest rank from major general to general, the source said. The planned changes are expected to be included in three key security documents to be revised by the end of this year. With the expansion of the infantry regiment, the source said the ministry is planning to also increase the number of units in charge of communications, taking care of facilities and supplying goods. The 15th brigade, based in the Okinawa prefectural capital of Naha, has become the vanguard to protect the Nansei Islands – a chain of islands including Okinawa stretching southwest from Kyushu toward Taiwan. Anti-US military base sentiment in Okinawa dips amid China tensions 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 US Marine Corps’ III Marine Expeditionary Force, also based in Okinawa. The Defence Ministry has continued to reinforce its Self-Defence Forces in Okinawa in light of China’s maritime expansion activities. In 2016, it established a coastal surveillance unit on Japan’s westernmost inhabited island of Yonaguni, located about 100 kilometres from Taiwan. Japan has also deployed missile units on Miyako and Amami-Oshima islands and plans to establish another on Ishigaki Island. Ishigaki is also not far away from the Diaoyu Islands – called the Senkakus by Japan – a group of uninhabited islets claimed by China, which repeatedly sends ships into Japanese waters around them. The 15th brigade, reorganised and upgraded from a smaller brigade in 2010, has about 2,200 members, whose mission includes safeguarding the Diaoyu Islands.