North Korea Tests First Submarine-Launched Missile in Two Years

SEOUL — North Korea on Tuesday conducted its first test in two years of a submarine-launched ballistic missile, just hours after special envoys on North Korea met in Washington to discuss how to deal with the isolated country’s nuclear capabilities.

The test was the latest in a series of provocations from North Korea in recent weeks, forcing the National Security Council of South Korea to discuss the North’s steady acts of aggression in the region. The council expressed “deep regret” that the North had launched a missile amid international efforts to continue dialogue.

The South Korean military said that the missile was fired from Sinpo, a city on the east coast where North Korea has often conducted its missile tests. It also has a naval base in the area, which is home to its submarine-launched ballistic missile program.

South Korea’s military provided no further details of the test while its officials continued to analyze data collected from the launch. The National Security Council at the South’s presidential office usually convenes when the North conducts a missile test to assess the dangers posed.

Along with its intercontinental ballistic missiles, North Korea’s submarine-launched ballistic missiles pose one of the biggest military threats to the United States and its regional allies because they can extend the range of the North’s nuclear missiles. S.L.B.M.s are also harder to detect in advance.

North Korea tested three Hwasong ICBMs in 2017. After the last such test, it claimed that it could now target the continental United States with a nuclear warhead. At the same time, the country has been developing a stealthier method of delivering its nuclear warheads through S.L.B.M.s.

North Korea ​has been ​testing its Pukguksong​ submarine-launched ballistic missiles since 2015. It conducted its last S.L.B.M. test in October 2019, when it launched its Pukgukgong-3 missile off its east coast. During military parades held in Pyongyang last October and in January, it also displayed two upgraded but untested versions of its Pukguksong missiles, called Pukguksong-4 and Pukguksong-5. The North called Pukguksong-5 a “strategic” S.L.B.M., indicating that it was designed to carry a nuclear warhead.

It remained unclear whether the S.L.B.M.s that the North has launched in recent years were fired from an actual submarine or a platform under the water. North Korea possessed only one submarine built to launch a ballistic missile and that vessel had only one launch tube. The country has been building a new one with greater capabilities.

On Tuesday, South Korean defense officials did not disclose whether they thought the latest test involved one of the North’s two new S.L.B.M.s or the new submarine it has been building.

Last month, South Korea conducted its first submarine-launched ballistic missile test. At the time, it called itself the seventh country in the world with S.L.B.M.s, after the United States, Russia, China, Britain, France and India, refusing to accept the North as a full-fledged S.L.B.M. power.

The two Koreas have been locked in an arms race as the North’s nuclear and missile capabilities expanded and the South has…