
SEOUL — North Korea launched two ballistic missiles off its east coast on Wednesday, the country’s first ballistic missile test in six months and a violation of multiple United Nations Security Council resolutions that ban North Korea from conducting such tests.
Hours after the missiles were launched, South Korea announced that its president, Moon Jae-in, had just attended the test of the country’s first submarine-launched ballistic missile, making South Korea the seventh country in the world to operate S.L.B.M.s, after the United States, Russia, China, Britain, France and India.
The missile tests by both Koreas on the same day dramatically highlighted the intensifying arms race on the Korean Peninsula as nuclear disarmament talks between Washington and North Korea remained stalled. They also underscored the growing concern over regional stability, with Prime Minister Yoshihide Suga of Japan calling the North Korean missile launch “outrageous” and a threat to peace.
In its announcement, South Korea revealed that it had successfully developed a supersonic cruise missile and a long-range air-to-land missile to be mounted on the KF-21, a South Korean supersonic fighter jet, and that it had developed a ballistic missile powerful enough to penetrate North Korea’s underground wartime bunkers.
test-fired what it called newly developed long-range cruise missiles over the weekend. But the United States has not imposed fresh sanctions against the North for weapons tests in recent years. When North Korea resumed testing short-range ballistic missiles in 2019, Donald J. Trump, then the president, dismissed them for being short range.
The Biden administration has said it would explore “practical” and “calibrated” diplomacy to achieve the goal of the complete denuclearization of the Korean Peninsula. But North Korea has yet to respond to the administration’s invitation to dialogue.
“Rather than strengthen sanctions and military exercises, the allies have emphasized a willingness for dialogue and humanitarian cooperation,” said Leif-Eric Easley, a professor of international studies at Ewha Womans University in Seoul. “The problem with less than robust responses to North Korea’s tests is that deterrence can be eroded while Pyongyang advances its capabilities and normalizes its provocations.”