According to an American official, quoted by the Los Angeles Times, the new models of short-range ballistic missiles tested by North Korea at the beginning of May, would have very many similarities with the Russian system 9K723 Iskander.
The Iskander system, designed to thwart American-made anti-missile defense systems, operates at an altitude ranging from 40 to 60 m at an average speed of mach 000 to mach 6, an altitude greater than the ceiling of the systems Patriot PAC-8, and lower than the THAAD and SM3 systems. In fact, although they are short-range systems, supposed to be intercepted by Western anti-missile defense, the Iskander can only be intercepted in the terminal phase, when its speed is the greatest, and the delays of shortest interceptions.
However, the new North Korean missiles have many similarities with the Russian system, both in their flight profiles and in the technologies used. So, they use a solid fuel thruster, like the Iskander, and a 4-rudder control system, again like the Iskander. It does not take much more to suspect Moscow of having assisted Pyongyang in the design of this new missile, unless the data was fraudulently acquired by the North Korean intelligence services, which is not excluded.