Yonhap news agency and the the NHK reporting. Kwon Jong-gun, North Korea’s director-general of American affairs says that Trump’s remarks that North Korea’s test of “smaller” ballistic missiles are not a problem because “a lot of other countries do it” effectively recognizes the North’s right to perform ballistic missile tests as a sovereign nation, calling it "self-defense".
Their recent tests include low-altitude ballistic missiles believed to be based on the Russian Iskandar tactical guided missile. This technology presents a challenge to many of the United States’ anti-ballistic missile defenses such as THAAD (stationed in South Korea) and Aegis (stationed in Japan) that presume a traditional parabolic trajectory. North Korea has also announced and it is believed by experts that North Korea is working on new long-range missile systems under the guise of “rockets” and a submarine capable of launching ballistic missiles.
While North Korea has not officially disclosed the purpose of these missiles, both are capable of carrying a nuclear warhead.