North Korea conducts nuclear test, South says
SEOUL — North Korea on Sunday conducted what appeared to be its sixth underground nuclear test, South Korean military officials said, in a brash move that surely threatens to heighten already tense relations in the region.
In just over a week, North Korea has test launched at least four ballistic missiles — including one that flew over Japan, causing serious alarm on the island — and boasted about creating a warhead that could, in theory, be used against the United States.
U.S. and South Korean officials say the detonation caused an unnatural tremor detected by sensors, a telltale sign of a nuclear test. The blast is believed to have occurred in a village in northeastern North Korea known as Punggye-ri — a site closely watched by international nuclear experts. The country’s five previous tests, including two last year, occurred there.
The magnitude of the nuclear test, North Korea’s first since last September, was estimated at 5.6, according to South Korean officials. The seismic wave occurred about 12:30 p.m. The size, if confirmed, would appear to have produced a yield similar to a test last year. Up to this point, the estimated yield has increased with each new test.
The latest experiment — a clear violation of international resolutions, though not unexpected by United States officials — raises new concerns that North Korea continues to advance as a nuclear state, despite years of effort by the international community to curb its atomic program.
The quake was felt just hours after North Korea boasted that a hydrogen bomb had been mounted on a new intercontinental ballistic missile and that leader Kim Jong Un had inspected the device.
North Korea, one of the world’s most isolated and unpredictable states, appears to be violating global norms with increased impunity. President Trump in April said “I don’t know” when asked whether a sixth nuclear test would trigger an American response.
Reactions from the international community weren’t immediately available, but condemnations from the United States, South Korea and Japan — all bracing in recent days from other provocations — were expected to be swift.
A negative reaction from China, North Korea’s most important trading partner and key player in any resolution, would also be likely.
The rogue state is still technically at war with South Korea, a United States ally that has roughly 28,000 American forces stationed on bases, largely within a few hundred miles of the shared Korean border.
Provocations in recent years, under dynastic young ruler Kim, have included numerous ballistic missile tests; the lengthy prison sentence given to an American tourist, who later died after being released; and a land mine incident along the border in 2015 that severely injured two South Korean soldiers.
The test is the latest provocation by the North, which in April paraded a massive battery of military hardware before the world in a recent celebration — including, perhaps, longrange devices capable of striking targets outside Asia.
In July, the country test launched what the international community now believes were intercontinental ballistic missiles — devices in theory capable of reaching the United States.
North Korea, which security experts say could have more than a dozen nuclear devices, first conducted an underground test in 2006. The tests’ power has increased, and last year state media reported advances in the miniaturization and manufacturing of nuclear warheads in addition to its strongest experiment to date last September.
“The standardization of the nuclear warhead will enable the DPRK to produce at will and as many as it wants a variety of smaller, lighter and diversified nuclear warheads of higher strike power,” the government said last September, using the initials of North Korea’s formal name, the Democratic People’s Republic of Korea.
Security experts in recent years have begun to shift their focus away from disarming the country to studying methods for deterring the country’s desire to use or share nuclear weapons.
In a visit to Seoul in March, Secretary of State Rex Tillerson called for a “different approach” for dealing with the North’s nuclear ambitions, acknowledging that previous administrations’ efforts to apply pressure and use covert actions have failed. It’s unclear what that approach might be, however.
A looming concern for U.S. officials is the extent to which China can — or is willing to — apply additional economic pressure to persuade the North to denuclearize, or perhaps to talk about it.