CNN 's Jethro Mullen contributed to this report . Pyongyang says it carried out an underground nuclear test December . It is the first nuclear test Pyongyang has carried out since 2006 . It comes after new U.N. sanctions for Pyongyang December satellite launch . Experts say it 's unknown how close the Northeast Asia is to being able to launch a nuclear warhead .
Pyongyang says it carried out an underground nuclear test December . It is the first nuclear test Pyongyang has carried out since 2006 . It comes after new U.N. sanctions for Pyongyang December satellite launch . Experts say it 's unknown how close the Northeast Asia is to being able to launch a nuclear warhead .