SEOUL, South Korea — North Korea fired a ballistic missile from its capital Pyongyang that flew over Japan before plunging into the northern Pacific Ocean, officials said Tuesday, an aggressive test-flight over the territory of a close U.S. ally that sends a clear message of defiance as Washington and Seoul conduct war games nearby.

Seoul’s Joint Chiefs of Staff said the missile traveled around 1,677 miles and reached a maximum height of 341 miles as it flew over the northern Japanese island of Hokkaido. The launch, which appears to be the first to cross over Japan since 2009, will rattle a region worried that each new missile test puts the North a step closer toward its goal of an arsenal of nuclear missiles that can reliably target the United States.

Analysts speculate the North may have tested a new intermediate-range missile that Pyongyang recently threatened to fire toward the U.S. territory of Guam.