Early evidence around North Korea's use of a bomb suggest that it may have been a "boosted" nuclear device — more powerful than what it's detonated before but far less dangerous than an H-bomb.
NBC News reports that it will take a couple of days for the U.S. to determine verify North Korea's claim that it detonated a hydrogen bomb.
Seismic data from Tuesday night's event would have shown a much greater force yield if hydrogen was involved, experts said. Instead, it was identical to the data collected after North Korea's tests in 2006, 2009 and 2013.
Air samples collected by drone should soon give analysts an idea of what happened, a senior U.S. military official said. But for the moment, the North Korean boast is being treated with skepticism.