Kim Jong Un

North Korean leader Kim Jong Un goes nuclear — and it might be for real this time.

The U.S. Navy is on high alert after Kim Jong Un ordered his military on standby to prepare for nuclear strikes on the U.S.

If there is a nuclear strike on the west coast of the United States, the radiation fallout alone would be catastrophic.

This is the latest in N. Korea’s increasing threats of nuclear war on the U.S.

But while many say the N. Korean leader’s threats aren’t credible, U.S. officials tell CNN that they believe North Korea’s claims of nuclear readiness are true because we can’t afford to underestimate him.

“The threat here is, to me right now, it’s a lot of bluster,” said Philip Yun, who heads a group that advocates nuclear disarmament. “For them to deliver on a threat, they have to have intent and they have to have capability. And quite frankly, I don’t think they have both.” — Yun told CNN the purpose of the news might be internal.

“Kim Jong Un has got a large party congress that’s going to be happening in May. And this is all about, for him, again, additional consolidation of power. He’ll want to get rid and justify getting rid of any enemies he may have.

“And this is part of a process where he is able to ratchet up the pressure, increase his control internally, and brandish his credentials to be ‘protecting the motherland.’ And so all of this sort of helps him internally even though it may not ring true to many of us here outside,” he said.