SEOUL, South Korea (AP) — Japan’s military said Wednesday it detected North Korea test-firing at least one ballistic missile, adding to its military demonstrations as tensions with Washington and neighbors escalate.

The launch comes days after North Korea offered a rare view into a secretive facility built to enrich uranium for nuclear bombs in a significant show of defiance against the United States and as leader Kim Jong Un called for a rapid expansion of his nuclear weapons program.

Japan’s Defense Ministry didn’t immediately provide more details Wednesday about the launch. Japan’s coast guard said the missile was believed to have already landed in sea and urged vessels to watch out for falling objects. Japan’s NHK television said the missile is believed to have landed outside of Japan’s exclusive economic zone.