SLBM

“These dimensional similarities indicate North Korea is still in the process of settling on a specific design for its next-generation SLBM,” it said.

Another previously unseen SLBM, designated the Pukguksong-5, was displayed at a military parade in January.

"If it's indeed an SLBM, it would only be in its rudimentary, infant stage."

The missile seemed to be a version of the South's Hyunmoo surface-to-surface ballistic missiles with the warhead part an imitation of India's K-15 SLBM, Jang said.

Jung Changwook, head of the private Korea Defense Study Forum in Seoul, said North Korea could perform a submarine-launched ballistic missile, or SLBM, test to upgrade its nuclear attack capability and put pressure on Washington after the U.S. presidential election in early November.