Should we believe North Korea's hypersonic missile claims?

North Korea's leader Kim Jong-Un is said to have personally overseen the successful test of a hypersonic missile he claimed would remarkably increase the country's nuclear "war deterrent".

A report by North Korean state media on Wednesday came a day after the suspected launch was detected by authorities in South Korea and Japan on Tuesday, leading to condemnation from officials in Washington and Tokyo causing further concern from the UN.

The Korean Central News Agency (KCNA) said Tuesday's launch involved a hypersonic glide vehicle, which, after its release from the rocket booster, demonstrated "glide jump flight" and "corkscrew manoeuvring" before hitting a sea target 621 miles away.

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Evidence of the launch and the threat

Photos released by the agency showed a missile mounted with a pointed cone-shaped payload soaring into the sky while leaving a trail of orange flames and Mr Kim watching from a small cabin with top officials.

The launch was reportedly North Korea's second test of its purported hypersonic missile in a week as Mr Kim continues a defiant push to expand his nuclear weapons capabilities in the face of international sanctions, pandemic-related difficulties and deadlocked diplomacy with the United States.

North Korea has been ramping up its testing activity in what experts see as an attempt to apply more pressure on rivals Washington and Seoul to accept it as a nuclear power in hopes of winning relief from economic sanctions.

But, should we believe the claims coming from North Korea?

Missile Defense Project Research Associate at the Center for Strategic and International Studies (CSIS), Masao Dahlgren, thinks so.

"I think that they should be taken seriously," he said."The missile threat posed by North Korea is not a joke.

"They have successfully flight-tested a number of weapons recently, a lot of short-range missile tests in the past year, and I think that these purportedly hypersonic missile tests are just another element to its burgeoning ballistic missile programme.

"I don't think that should be discounted, or dismissed as hot talk."

Watch: Pictures of what North Korea claimed was a successful test flight of a hypersonic missile.

Mr Dahlgren thinks the missile threat from North Korea is "real" and added: "North Korea's advancement in its missile capabilities, its production of long-range solid-fueled missiles, its production of missiles with manoeuvring payloads, such as the one we saw tested recently, its development of new cruise missiles, I think, shows a serious advancement in capability."

The hypersonic missiles

Hypersonic weapons, which fly at speeds in excess of Mach 5, or five times the speed of sound, could pose crucial challenges to missile defence systems because of their speed and manoeuvrability.

It is unclear whether and how soon North Korea could manufacture such a high-tech missile, but it was among a wish-list of sophisticated military assets Mr Kim disclosed early last year along with a multi-warhead missile, spy satellites, solid-fueled long-range missiles and underwater-launched nuclear missiles.

At CSIS, Mr Dahlgren focuses on deterrence and emerging technologies.

Answering if North Korea do, in fact, have hypersonic missiles, he said: "It's important to note that this isn't similar to the hypersonic weapon systems that are often talked about being tested by the US, Russia or China.

"It's a class of missile that experiences hypersonic flight near the end of its flight regime and it's capable of manoeuvring in that end portion.

Mr Dahlgren added: "But it's markedly different from hypersonic weapons we are seeing from China which can manoeuvre throughout their entire flight envelope."

Watch: What are hypersonic missiles? We took a closer look in October 2021.

The 'successful' launch and 'strategic' significance

The KCNA said Mr Kim praised the accomplishments made by his military scientists and officials involved in developing the hypersonic missile system.

A system he described as the most significant part of a new five-year plan announced in early 2021 to build up the North's military force.

The North has described the new missile as part of its "strategic" weaponry, implying that the system is being developed to deliver nuclear weapons.

Mr Dahlgren said: "I think nearly all of those missiles that North Korea developed could be adapted to carry nuclear weapons, certainly."

"I think what's more strategic than just the weapon itself, is the technology it represents."

"Maybe when Mr Kim talks about them being strategic weapons, it's not only in reference to them being nuclear but in the sense that it represents a strategically important advancement in their missile capability."

Experts say North Korea is likely years away from acquiring a credible hypersonic system.

But Mr Kim's attendance at Tuesday's launch along with the state media's description of a "final test-fire" indicated that the North was possibly moving towards deploying the weapon relatively soon.

KCNA said: "The superior manoeuvrability of the hypersonic glide vehicle was more strikingly verified through the final test-fire."

Watch: How much of a concern is North Korea's new missile?

Response from the South

South Korea's Joint Chiefs of Staff said the North Korean missile flew 434 miles at a maximum speed of about Mach 10 before landing in waters off the North's eastern coast.

South Korea's Defence Ministry had played down North Korea's earlier test on 5 January, insisting that the North exaggerated its capabilities after testing a conventional ballistic missile and expressing doubt that the North had acquired the technologies needed for hypersonic weapons.

Following Tuesday's launch, the Joint Chiefs of Staff said in a statement that the North demonstrated more advanced capability compared to its previous test, but did not elaborate further.