North Korea launched a Hwasong-15 intercontinental ballistic missile (ICBM) on Saturday as a warning to the U.S. and South Korea and to test the readiness of special units under the military’s new Missile General Bureau, according to state media.

The Korean Central News Agency (KCNA) reported Sunday that the launch ordered on short notice proves the reliability of Pyongyang’s nuclear weapons and “capacity for fatal nuclear counterattack on the hostile forces,” stating “military threats of the U.S. and south Korea are getting serious to the extent that can not be overlooked.”