The United States continues upgrading its air power in Japan, as older F-16 fighter jets make way for F-35 stealth aircraft amid threats from Russia, China and North Korea.

"The U.S. will continue to provide the necessary capabilities to support the defense of Japan throughout this modernization effort," the Pacific Air Forces told Newsweek .

Newsweek has emailed the Russian and Chinese foreign ministries for comment. North Korea 's embassy in Beijing did not immediately respond to a request for comment.

Why It Matters

Japan is a major U.S. security ally in Northeast Asia, central to Washington's island chain strategy to keep adversaries at bay. More than 50,000 American troops are stationed there and the Pentagon has sent some of its most capable units to the country, inclu

See Full Page