SEOUL, South Korea (AFP) — North Korea said Thursday it had test-fired one of its newest and most powerful missiles to boost its nuclear deterrent, Kim Jong Un’s first weapons test since being accused of sending soldiers to Russia.

Seoul had warned a day earlier that the nuclear-armed North was preparing to test-fire another intercontinental ballistic missile (ICBM) or even conduct a nuclear test ahead of next week’s United States elections.

The launch came just hours after US and South Korean defense chiefs called on Pyongyang to withdraw its troops from Russia, warning that North Korean soldiers in Russian uniforms were being deployed for possible action against Ukraine.

“The initial judgment so far is that (Pyongyang) may have test-fired a new solid-propelled long-range ballistic missile,” Seoul’s military said, adding the missile had flown around 1,000 kilometers after being fired on a lofted trajectory — meaning up, not out.

Developing advanced solid-fuel missiles — which are quicker 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 meets the purpose of informing the rivals... of our counteraction will,” the official Korean Central News Agency reported Kim as saying.

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

Tokyo said that the “ICBM-class” missile had flown for longer than any other previously tested by the North, being airborne for about 86 minutes and hitting altitudes of 7,000 kilometers.

“We estimate that its flying altitude was the highest we have seen,” Japanese defense minister Gen Nakatani told reporters.

Washington slammed the launch as “a flagrant violation of multiple United Nations (UN) Security Council resolutions,” National Security Council spokesperson Sean Savett said in a statement.

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

South Korean President Yook 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 “habitual violations of Security Council resolutions.”

‘Withdraw troops’

The US and South Korean defense chiefs called Wednesday for North Korea to withdraw its troops from Russia, where Washington says some 10,000 of them have been deployed for possible action against Ukrainian forces.

“I call upon them to withdraw their troops out of Russia,” US Defense Secretary Lloyd Austin said at the Pentagon, echoing a call by his South Korean counterpart Kim Yong-hyun, who stood beside him.

Kim, speaking through a translator, said he believes the North Korean deployment to Russia “can result in the escalation of the security threats on the Korean peninsula.”

That is because there is a “high chance” that Pyongyang will ask for technology transfers from Russia to aid its weapons programs — including on tactical nuclear weapons, ICBMs and reconnaissance satellites — in exchange for the deployment of its forces, he said.