The missiles bear a strong resemblance to the Russian-designed Iskander, a short-range, nuclear-capable ballistic missile that has been in the Russian arsenal for more than a decade.

“There are Russian technology fingerprints all over it,” said Marcus Schiller, a leading expert on North Korean missiles who is based in Germany.

He added that short of actually procuring the missiles from Russia, the North could have had key parts delivered from somewhere else, perhaps not directly from Russia, while making components such as the outer shell, or airframe, domestically.

The Iskander, or something like it, would be of particular interest to North Korea.