South Korea’s military says it has detected that North Korea has fired at least one ballistic missile toward its eastern waters.

South Korea’s Joint Chiefs of Staff didn’t immediately say what type of missile it was or how far it flew.

Tensions on the Korean Peninsula are at their highest point in years, with the both the pace of North Korean weapons demonstrations and South Korea’s combined military exercises with Japan intensifying in a cycle of tit-for-tat.

The weapons North Korea tested this year included intercontinental ballistic missiles that demonstrated potential range to reach the U.S. mainland and a series of launch events that the North described as simulated nuclear attacks on targets in South Korea.