Developing advanced solid-fuel missiles — which are faster to launch and harder to detect and destroy in advance — has long been a goal for Kim.

North Korea defended the sanctions-busting launch, calling it “an appropriate military action that fully fulfills the purpose of informing rivals … of our will to counter,” Kim, the official Korean Central News Agency, said .

The test “updated the recent records of North Korea’s strategic missile capability,” it said, with Kim vowing that his country “will never change its line of strengthening its nuclear forces.”

Washington called the launch “a flagrant violation of several UN Security Council resolutions,” National Security Council spokesman Sean Savett said in a statement.

Seoul, Washington and Tokyo – key regional security allies – will respond with joint military exercises involving strategic US assets, Seoul said.

South Korean President Yoon Suk Yeol also said the country would “designate new independent sanctions” on the North and work with partners and the UN to penalize Pyongyang’s “regular violations of Security Council resolutions.”

Diverting attention

North Korea’s missile launch “appears to have been carried out to deflect attention from international criticism of its troop deployment,” Yang Moo-jin, president of the University of North Korean Studies in Seoul, told AFP.

Seoul has long accused the nuclear-armed North of sending weapons to help Moscow fight Kiev and has claimed Pyongyang has moved to deploy troops en masse following Kim Jong Un’s signing of a mutual defense agreement with Russian President Vladimir Putin in June.

The deployment of troops poses a “significant security threat”, Seoul said, and US Defense Secretary Lloyd Austin on Wednesday called on the North to withdraw its troops.

The duration and altitude of Thursday’s missile launch indicate the North “tried to assess whether a heavy ICBM with multiple warheads can actually reach the US mainland,” Yang added.

South Korea’s military warned lawmakers a day earlier that preparations were “almost complete for a long-range ICBM-class missile” and that a launch could be aimed at testing the North’s atmospheric re-entry technology.

Seoul has warned that Russia could provide Pyongyang with new technology or expertise in exchange for weapons and troops to help it fight Ukraine.

It is possible that “Russia actually provided new technologies for re-entry into the atmosphere,” Ahn Chan-il, a defector-turned-researcher who heads the World Institute for North Korean Studies, told AFP.

But it’s more likely that Thursday’s test was an attempt to distract from the troop deployment and get “the world’s attention ahead of the US presidential election,” Ahn added.

Seoul, a major arms exporter, said it was examining whether that was the case send arms directly to Ukraine in response, something it has previously resisted due to long-standing domestic policy that prevents it from sending weapons into active conflicts.

North Korea has denied sending troops to Russia, but in its first comments in state media last week, its deputy foreign minister said that if such a deployment were to happen, it would be in accordance with international law.

Pyongyang is barred from tests using ballistic technology by several rounds of UN sanctions, but leader Kim has stepped up launches this year, with experts warning he may test weapons before supplying them to Russia.