North Korea unveiled details of Monday’s short range missile launch into the East Sea, saying it was a “new type large-caliber multiple rocket launching system (MRLS)” on Tuesday via the state run newspaper Rodong Sinmun.

The South Korean Joint Chiefs of Staff (JCS) and the Ministry of Defense (MND) speculated the rockets were MRLS with a 300mm caliber, at a regular press briefing on Tuesday. Previously, observers guessed the missile from North Korea seemed like an improved version of KN-02, a surface-to-surface missile.