In a joint announcement on Tuesday, South Korea, Japan and the United States said they had activated a system to detect and assess North Korea's missile launches in real-time and established a multi-year trilateral military exercise plan.
Separately, national security officials of the three countries held a video conference about curbing North Korea's illicit cyber activities, which may be channeling funds to its weapons programs, South Korean President Yoon Suk Yeol's office said.
North Korea said on Tuesday it had tested the isolated state's newest ICBM on Monday to gauge the war readiness of its nuclear force against mounting U.S. hostility, as Washington and its allies began operating a real-time missile data sharing system.
North Korean state media said leader Kim Jong Un watched Monday's launch of the Hwasong-18 intercontinental ballistic missile (ICBM) at a site east of the capital, Pyongyang. The missile reached an altitude of 6,518 km, flying 1,002 km and accurately hitting the intended target, an empty patch of sea, state media said.
Kim said the launch sends "a clear signal to the hostile forces, who have fanned up their reckless military confrontation hysteria" against the North, state news agency KCNA reported.
Kim said the drill "displayed the DPRK's will for toughest counteraction and its overwhelming strength." DPRK is short for the Democratic People's Republic of Korea.
He presented "some new important tasks for accelerating the development of the DPRK's nuclear strategic forces," KCNA said, without elaborating.
South Korea said Monday's missile launch was a solid-fuel Hwasong-18. It flew in a sharply lofted trajectory and landed in the sea west of Japan's Hokkaido island.
North Korea's state media published what it said were photographs of the launch, showing the missile blasting off from a snow-covered field trailing a plume of smoke.
North Korea's description of a "launching drill" was its first such characterization for an ICBM and showed it went beyond developmental testing to assess counteraction capabilities, Jenny Town, director of the Washington-based 38 North project, said on X.
The ICBM's lofted trajectory and 74-minute flight time are compatible with an operational range of up to 15,000 km if launched at a flatter, standard trajectory, which puts all of the mainland United States within reach, Japanese defense
officials said.
The launch was condemned by South Korea, Japan and the United States as a flagrant violation of U.N. Security Council resolutions.
On the same day, China, a Security Council permanent member that has previously approved sanctions against Pyongyang, held a high-level meeting with North Korea in Beijing, discussing cooperation and issues of "common concern" in "a friendly
atmosphere," the countries' state media said.
The U.N. Security Council is due to meet on Tuesday at the request of the United States and other countries to discuss the launch.
South Korea’s Yoon, who has taken a hard line against Pyongyang since taking office last year, said Kim Jong Un's regime "will come to realize provocative actions will only bring greater pain to itself."
