North Korea said Wednesday that it successfully staged its first test of a more powerful form of a nuclear weapon, expanding the U.S.’s foreign-policy challenges and highlighting the limits of China’s ability to rein in its volatile ally.
An announcer on North Korean state television said in a midday broadcast that scientists had successfully detonated a hydrogen bomb at around 10 a.m. local time.
The U.S. Geological Survey reported that a magnitude 5.1 earthquake was detected at that time near North Korea’s nuclear test site in the northeast of the country.
