The Thursday launch was the first time Pyongyang has fired Kim's most powerful missiles at full range since 2017.

It appears to have travelled higher and further than any previous ICBM tested by the nuclear-armed country -- including one designed to strike anywhere on the US mainland.

The test-launch of the "new type inter-continental ballistic missile" was conducted under the "direct guidance" of leader Kim, KCNA reported.

State media photographs showed Kim, wearing his customary black leather jacket and dark sunglasses, striding across the tarmac in front of a huge missile, with other images of him cheering and celebrating the test launch with uniformed military top brass.

The new ICBM "would make the whole world clearly aware of the power of our strategic armed forces once again," Kim said, according to KCNA, adding the country was now "fully ready for long-standing confrontation with the US imperialists".

- 'Monster missile' -

Known as the Hwasong-17, the giant ICBM was first unveiled in October 2020 and dubbed a "monster missile" by analysts.

It had never previously been successfully test-fired, and the launch prompted immediate outrage from Pyongyang's neighbours and the United States.

"The missile, launched at Pyongyang International Airport, travelled up to a maximum altitude of 6,248.5 kilometres and flew a distance of 1,090 km for 4,052s before accurately hitting the pre-set area in open waters" in the Sea of Japan, KCNA said.

South Korea's military had estimated the range of the Thursday launch as 6,200 km (3,900 miles) -- far longer than the last ICBM, the Hwasong-15, which North Korea tested in November 2017.

The missile landed in Japan's exclusive economic zone, prompting anger from Tokyo, but KCNA said the test had been carried out "in a vertical launch mode" to ease neighbours' security concerns.

Following Thursday's test, Washington imposed new sanctions on entities and people in Russia and North Korea who are accused of "transferring sensitive items to North Korea's missile program".

The North is already under biting international sanctions for its weapons programs, and the UN Security Council will hold an emergency meeting over the launch on Friday.

- 'Important progress' -

The test is a clear sign North Korea has made "important qualitative progress" on its banned weapons programs, said US-based analyst Ankit Panda.

"What's important about this ICBM is not how far it can go, but what it can potentially carry, which is multiple warheads," something North Korea has long coveted, he told AFP.

"The North Koreans are on the cusp of significantly increasing the threat to the United States beyond the ICBM capability demonstrated in 2017."

Multiple warheads would help a North Korean missile evade US missile defence systems.

The North had carried out three ICBM tests prior to Thursday, the last being the Hwasong-15 in 2017.

Long-range and nuclear tests were paused when Kim and then-US president Donald Trump engaged in a bout of diplomacy which collapsed in 2019. Talks have stalled since.

Thursday's launch, one of nearly a dozen North Korean weapons tests this year, marked a dramatic return to long-range testing.

It came just days after one last week, likely also of the Hwasong-17, ended in failure, exploding after launch.

- Compensation -

"This test also appears to 'compensate' for last week's failed projectile launch -- handsomely so," Soo Kim, RAND Corporation Policy Analyst and former CIA analyst, told AFP.

"The regime appears quite pleased with the outcome of the test," she added.

KCNA said that the launch proved the weapon worked and that its operation could now be guaranteed even "under wartime environment".

The country's new ICBM launch comes at a delicate time for the region, with South Korea going through a presidential transition until May, and the US distracted by Russia's invasion of Ukraine.

Analysts say the drive to successfully test-fire the Hwasong-17 is part of Pyongyang's preparations to mark the 110th anniversary of the birth of founder Kim Il Sung on April 15.

The official Rodong Sinmun newspaper carried a photograph of a haggard-looking Kim signing papers at his desk, with an image of a handwritten "I approve the test launch" scrawled over a report.

"Kim Jong Un wants to ultimately establish himself as a leader who has successfully developed both nuclear weapons and ICBMs," Ahn Chan-il, a North Korean studies scholar, told AFP.

"He is almost desperate as without such military achievements, he really hasn't done much," he added, pointing to the isolated country's Covid- and sanctions-battered economy.