North Korea appears able to mount a miniaturized nuclear warhead on a missile but is still struggling with missile re-entry technology necessary for longer range strikes, a senior U.S. military official said on Thursday.

“I think they could mate a warhead with a delivery device. They’re just not sure (about) re-entry,” said the official, speaking to reporters on condition of anonymity.

“They’re endeavoring to overcome that.”

North Korea has carried out repeated nuclear and missile tests this year in defiance of U.N. Security Council resolutions and sanctions and claims it has the capability to mount a nuclear warhead on a missile. […]