TOKYO — North Korea has continued its development of intercontinental ballistic missiles despite declaring a halt to launches, having conducted a missile-linked radio wave experiment early this month, it has been learned.
Despite sanctions limiting the North’s petroleum supply, the North Korean military is continuing to train at its usual levels. In response, the Japanese and U.S. governments plan to increase their surveillance of smuggling and other activities on the high seas, according to military and diplomatic sources.
North Korea conducted a launch test of its radio telemetry, which is transmitted from equipment in a missile’s components such as a warhead. When a ballistic missile is launched, telemetry provides essential information about the missile’s angle, location, speed and other factors to observers on the ground.
In 2016 and 2017, North Korea launched about 40 missiles, including ICBMs. Ground-based telemetry tests are often conducted prior to an ICBM launch, and are considered an important sign of an impending missile launch.
The U.S. military, Japan Self-Defense Forces and South Korean military are constantly monitoring North Korea for radio waves.
According to the sources, the tests have two objectives: first, to serve as a check on the United States due to a lack of progress in negotiating a relaxation of sanctions; and second, as a necessary part of missile development.
North Korea’s last ballistic missile launch came in November 2017. In April, a plenary meeting of the Central Committee of the Workers’ Party of Korea adopted a decision stating a halt to nuclear weapons testing and ICBM test launches.
However, Japanese, U.S. and South Korean defense authorities believe North Korea has maintained a posture that would enable it to resume missile launches.
Analysis of satellite images and other data has indicated that since the start of the year, the North Korean Navy and Air Force have been training at roughly the same intensity as in other years.
The U.N. Security Council last December approved additional sanctions on North Korea limiting imports of refined petroleum products to 500,000 barrels per year. Nevertheless, the frequency of military drills and other matters have not changed compared to before the resolution, the sources said.