BBC News
KCNA said it “precisely hit” a set target 700km (434 miles) away.
This is the second reported test of a hypersonic missile, which can avoid detection for longer than ballistic missiles.
The test comes as its leader Kim Jong-un had earlier vowed to bolster Pyongyang’s defences.
Mr Kim said in a New Year’s speech that Pyongyang would continue to strengthen its defence capabilities due to an increasingly unstable military environment on the Korean peninsula.
North Korea tested a variety of missiles last year amid stalled talks with the South and US.
Pyongyang joins a small number of countries, including the United States and China, in attempting to develop this weapon.
The latest launch was first detected by the Japanese coast guard early on Wednesday, before being confirmed by defence authorities in Seoul.
In Wednesday’s test, the “hypersonic gliding warhead” detached from its rocket booster and manoeuvred 120 km (75 miles) laterally before it “precisely hit” a target 700 km (430 miles) away, KCNA reported.
It said the test also confirmed components such as flight control and its ability to operate in the winter.
Hypersonic weapons usually fly towards targets at lower altitudes than ballistic missiles and can achieve more than five times the speed of sound – or about 6,200 km per hour (3,850 miles per hour).
The tests come as Pyongyang struggles with food shortages due to a coronavirus blockade that has severely affected its economy.
At the end-of-year meeting, Mr Kim said the country was facing a “great life-and-death struggle”, adding that increasing development and improving people’s living standards were among this year’s goals.
Despite this, North Korea shows no sign of slowing down its weapons program, saying they are needed for its own self-defence.
The US has been calling for North Korea to give up its nuclear weapons, and Pyongyang’s relationship with President Joe Biden’s administration has so far been fraught with tension.