Pyongyang "successfully conducted the separation and guidance control test of individual mobile warheads" on Wednesday," KCNA reported, adding that the "separated mobile warheads were guided correctly to the three coordinate targets."

"The test is aimed at securing the MIRV capability," it said, referring to multiple independently targetable reentry vehicle technology -- or, the ability to fire multiple warheads on a single ballistic missile.

The statement came a day after South Korea's military said the North had test-fired what appeared to be a hypersonic missile on Wednesday, but the launch ended in a mid-air explosion.

The missile took off from an area in or around Pyongyang at about 5:30 am (2030 GMT) and South Korean and US intelligence agencies were conducting a detailed analysis, Seoul's Joint Chiefs of Staff said in a statement.

The JCS official said the test of what appeared to be a hypersonic missile ended in failure after a journey of some 250 kilometres (155 miles).

More smoke than usual appeared to emanate from the missile, raising the possibility of combustion issues, the official said, adding it may have been powered by solid propellants.

Japan also confirmed the launch, with its coast guard saying the missile splashed down in the Sea of Japan, also known as the East Sea.

According to KCNA, the test "was carried out by use of the first-stage engine of an intermediate-range solid-fuel ballistic missile within a 170-200 km radius."

"The effectiveness of a decoy separated from the missile was also verified by anti-air radar," it said.

The test follows North Korea launching hundreds more trash-carrying balloons southward on Monday and Tuesday, the latest in a series of border barrages that have sparked a tit-for-tat propaganda campaign.

Late Wednesday, South Korea's military said the North has again floated another round of trash-carrying balloons southward for the third consecutive day, advising the public to report the balloons if spotted and refrain from touching them.

In response, Seoul has fully suspended a tension-reducing military deal and restarted some propaganda broadcasts from loudspeakers along the border.

Meanwhile, South Korea's Marine Corps resumed live-fire exercises on islands near the western inter-Korean border on Wednesday, marking the first such exercises since a 2018 tension-reducing military deal with the North was suspended earlier this month over the balloon-borne propaganda.

South Korea and the US also staged joint air drills Wednesday involving around 30 aircraft, including Washington's advanced stealth fighter jet, F-22 Raptor.

On Tuesday, President Yoon Suk Yeol visited a US aircraft carrier that arrived in South Korea at the weekend for joint military drills aimed at countering North Korean threats.

The drills, which include Japan, are set to go ahead later this month.

Pyongyang has routinely criticised such exercises as rehearsals for an invasion.