SEOUL, South Korea — South Korea’s military says North Korea has fired at least one ballistic missile into the sea.

The Joint Chiefs of Staff on Saturday didn’t immediately say what type of missile was launched or how far it flew.

The launch came a day after North Korea’s Foreign Ministry threatened to take “unprecedently” strong action against its rivals after South Korea announced a series of planned military exercises with the United States aimed at sharpening their response to the North’s growing threats.