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 countered by deploying more powerful warplanes and missiles of its own.
North Korea conducted its last missile test on Sept. 30, when it test-launched a newly developed antiaircraft missile. Outside officials and analysts closely watch North Korean weapons launches because some of the country’s missiles are capable of carrying nuclear warheads.
North Korea’s weapons have become a growing security concern in the region. The country has conducted eight missile tests this year, including missiles launched from trains rolled out of tunnels and what the North claimed was a hypersonic missile. Last week, it showed off its growing arsenal of missiles in one of its largest-ever exhibitions of military gear, as its leader, Kim Jong-un, said he didn’t believe the United States’ repeated assertions that it harbored no hostile intent toward his country.
Multiple resolutions by the United Nations Security Council ban North Korea from developing and testing ballistic missile technology. In 2017, North Korea test-launched three intercontinental ballistic missiles and conducted its sixth underground nuclear test. By the end of that year, Mr. Kim claimed that his country had the ability to launch a nuclear strike against the continental United States.
He then met with President Donald J. Trump three times to push the United States to ease sanctions. Their diplomacy collapsed without an agreement on rolling back the North’s nuclear weapons program or lifting international sanctions imposed on the country.
Mr. Kim has since resumed his missile tests. During a meeting of the North’s ruling Workers’ Party in January, Mr. Kim provided a detailed list of weapons that he said his country was developing to help counter foreign aggression.
Sung Kim, Washington’s special envoy on North Korea, renewed his call for dialogue on Monday with Pyongyang when he met with his South Korean and Japanese counterparts in Washington. He reiterated that the United States held “no hostile intent” toward the North, and urged the country to return to talks “without conditions.”