Kim Jong-un oversaw his sixth missile test for 2017 from the northwestern city of Kusong early on Sunday.
North Korea later claimed the missile was capable of carrying a nuclear warhead and reached a distance of 489 miles.
Initial reports suggested that it may have been a new intermediate range missile, but US officials have revealed it was more likely a KN-17 medium range rocket.
The US Pacific Command and US Strategic Command reportedly believe the missile was tested with the intent of using it as an anti-ship rocket amid the US Navy amassing at the Korean peninsula.
North Korea previously made three failed attempts to launch a KN-17 last month, but the latest development has reportedly raised concerns in the Pentagon.
It is understood the failures had made it difficult for the US to determine the KN-17’s full range capabilities.
But Japanese officials believe Sunday’s missile flew for about 30 minutes and travelled 500 miles at an unusually high altitude of 1,240 miles.
South Korean military claim the missile travelled a slightly lesser distance of 430 miles.
The KN-17 is a single-stage, liquid-fuelled missile, which can be launched with five minutes notice from a concealed location.
North Korea has continued with its missile programme despite sanctions by the United Nations Security Council.
Kim Jong-un has revealed his goal is to develop a missile capable of carrying a nuclear warhead to the US mainland.
Last month the rogue state unveiled its new missile arsenal at a military parade through Pyongyang and released a series of propaganda videos obliterating parts of the US.
The UN Security Council said on Sunday it will hold urgent consultations about North Korea’s latest ballistic missile test at the request of the United States, Japan and South Korea.