U.S. and Japan Say They Will Strengthen Military Cooperation

The agreement will not increase the number of Marines serving in Okinawa, officials said. But it will allow Marines to more quickly deploy if tensions intensify in the region. Pentagon officials said the restructuring is in part to deal with China’s growing military activity and presence, including around the island of Taiwan, a self-governing democracy that the Chinese Communist Party intends to bring under its rule.

Russia’s full-scale invasion of Ukraine last year has made American, Taiwanese and Japanese officials more anxious about the possibility of China trying a move on Taiwan — perhaps not in the coming months or years, but maybe by the end of the decade. Much depends on how Chinese officials perceive the balance of military strength in the region, which includes American forces, U.S. officials say.

In August, China alarmed Japan when it fired ballistic missiles in the waters around Taiwan to send a message of aggression to the island and to the United States after Speaker Nancy Pelosi visited in a show of support. Five of the missiles landed in the exclusive economic zone off Japan’s coast, the first such occurrence.

Japanese officials have also been disquieted by a series of joint military exercises conducted by China and Russia in the region. The two nations held one such exercise in May, the first one they had done together since Russia invaded Ukraine. Mr. Biden was visiting Tokyo at the time for a meeting of the Quad, a coalition of the United States, Japan, India and Australia that was formed in part to counter China’s growing power.

China and Japan have not resolved territorial disputes over waters and islands in the East China Sea. The Japanese and American militaries have noted increased Chinese maritime activity in the area, U.S. officials said.

Japan’s bolstering its military capabilities is likely to cause greater unease in South Korea to some degree, given the bitter memories there of Japan’s violent occupation of the Korean Peninsula, which still has a profound effect on relations between the two countries. But the United States has been pressing both nations, which share security interests and concerns, to maintain working ties. Besides China, the two countries and the United States are worried about the nuclear weapons program and military actions of North Korea.

The government run by Kim Jong-un, the ruler of North Korea, launched more than 90 ballistic and other missiles in 2022, more than in any other year. It has continued to conduct missile launches this year. American, Japanese and South Korean officials are bracing for a potential nuclear test by North Korea.