Japan's Defense Ministry says its Maritime Self-Defense Force conducted joint missile defense exercises with the US and South Korean Navies on Monday on the Sea of Japan.
The ministry says the drills involve the three nations' ships equipped with the Aegis radar system, which can track ballistic missiles.
This is the first three-way drill using the scenario of a ballistic missile launch since February. They checked procedures for sharing information about fired missiles.
The ministry says Monday's drill will promote trilateral cooperation as the security situation in the region is growing more challenging.
It says the drill symbolizes the three nations' commitment to defending an international order based on the rule of law.
On Thursday, North Korea test-fired what could be a new model of an intercontinental ballistic missile that uses solid fuel. Japan's defense ministry is trying to confirm what type of missile was launched. A solid-fuel ICBM can be launched quicker than a liquid-fuel ICBM.