North Korea is presumed to have launched a new type of solid-fuel intermediate-range ballistic missile (IRBM) using technology related to submarine-launched ballistic missiles (SLBM), South Korea’s Joint Chiefs of Staff (JCS) said on Monday.

The missile, named “Pukguksong-2” by the North’s state-run media, is related to the Pukkuksong-1 SLBM, which was reportedly successfully launched in late August.

South Korea’s JCS said the military understood that the North had used a “cold-launch system” to launch the IRBM, pointing to the North Korean media’s claim on Monday that the test-fire “proved the reliability and security of cold eject launch system