According to the report, North Korea also test-fired a new anti-aircraft missile in the Yellow Sea this week.
The report said a "certain goal" was achieved through the test launch.
The warhead was designed for the "Hwasal-1 Ra-3" strategic cruise missile, and the new anti-aircraft missile was the "Pyoljji-1-2," it said.
Both tests were reportedly part of the regular activities of the North Korean missile administration.