Factbox-The 'monster missile' that may be involved in N.Korea's biggest ICBM test

FILE PHOTO: A view of the newly developed intercontinental ballistic rocket Hwasong-15's test that was successfully launched is seen in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang November 30, 2017. REUTERS/KCNA/File Photo

SEOUL (Reuters) - North Korea conducted what would be its largest intercontinental ballistic missile (ICBM) test ever on Thursday, according to South Korea and Japan, bringing new attention to a massive new missile that may be under development.

North Korea has not confirmed what missile was involved in the test, but it came after officials in Seoul and Washington said launches on Feb. 27 and March 5 involved parts of the Hwasong-17 ICBM system, likely in preparation for eventually conducting full test like the one on Thursday.