North Korea Says It Tested a Hydrogen Bomb Meant for Missiles
North Korea carried out its sixth and most powerful nuclear test early Sunday in an extraordinary show of defiance against President Trump, who responded by declaring the country “hostile and dangerous to the United States” and criticizing an American ally, South Korea, for “talk of appeasement.”
The underground blast, which caused tremors that were felt in both South Korea and China, was the first by the North to clearly surpass the destructive power of the bombs dropped on the Japanese cities of Hiroshima and Nagasaki in World War II.
The government said it had tested a hydrogen bomb that could be mounted on an intercontinental ballistic missile, and hours before the detonation, it released photographs of its leader, Kim Jong-un, examining what it said was the new weapon.
Hydrogen bombs are vastly more powerful than ordinary atomic weapons, and though some analysts were skeptical of the North’s claim, the early estimate of outside experts was that the weapon detonated underground Sunday morning was most likely four to sixteen times more powerful than any the North has detonated before.
Hours after the test, Defense Secretary Jim Mattis emerged from a meeting with Mr. Trump to warn the country that “any threat to the United States or its territory, including Guam or our allies, will be met with a massive military response.”
The tremor from the North was strong enough to be felt by some people in South Korea. The South’s National Fire Agency, which operates an emergency hotline, said it had received 31 calls about buildings and the ground shaking, the first time that South Koreans had reported tremors after a North Korean nuclear detonation.
The blast was so powerful that the first tremor was followed by a second, weaker one minutes later, which the United States Geological Survey called a “collapse.”
The second tremor was detected in China but not in South Korea; officials in the South said that would be consistent with a cave-in at the North’s underground test site.