(CNN) – New details of North Korea’s plan to expand its nuclear arsenal with more and even deadlier weapons. And now Dictator Kim Jong Un is speaking out about how he might use them. Appearing in a dark business suit, Kim Jong Un signals to his enemies what could provoke him to launch a nuclear warhead.

Kim Jong Un: “Our republic will not use a nuclear weapon unless its sovereignty is encroached upon by any aggressive, hostile forces with nuclear weapons.”

But would Kim only play defense with nuclear weapons?

His regime has declared it is expanding its nuclear force “in quality and quantity”.

David Albright, Institute for Science & International Security said, “It doesn’t appear North Korea wants to slow down its nuclear weapons program. It appears that they want to make more nuclear weapons, and they want to make those weapons more deadly.”

Tonight US officials tell CNN, they’re preparing for a provocation from North Korea. A u-s intelligence official says it’s expected the regime will again test a nuclear bomb.

The monitoring group ’38 north’ released new satellite images of the Punggye-Ri nuclear test site which, it says, indicate a test could come soon.

David Albright, Institute for Science & International Security said, “There’s still vehicles at the test site. But there’s reduced activity at the test site. And that can be an indication of overall clearing out, in preparation for actually conducting a test.”

The latest assessment from weapons experts is that the ambitious, unpredictable North Korean leader now has between 10 and 20 nuclear bombs and as many as eight types of missiles which can deliver them. He likely can miniaturize his warheads to fit on medium-range missiles that can hit South Korea, japan, or the US territory of Guam.

Analysts say they can probably fit a warhead onto a long-range missile capable of hitting the US. But they haven’t flight-tested those missiles, to survive re-entry. The danger: even when a North Korean test fails, this regime succeeds.

Alexandre Mansourov, Johns Hopkins University said, “Every time they conduct a nuclear test, they resolve a technical puzzle, or they overcome a technical problem uh which they had before.”

This comes as Kim closes his workers’ party congress. Analysts say this event following his bloody purges of top generals crowns Kim’s effort to shift power away from his military and toward himself.

Ken Gause, North Korea Leadership Expert, CAN said, “The military has been for all intents and purposes neutered within the leadership. The key positions of power within the leadership have been turned over multiple times. So I see it highly unlikely that the military can challenge Kim Jong Un at this point.”

This workers’ party congress is seen as a coronation of Kim. But as he elevates his own power, and the generals lose theirs. Experts are worried that, at a moment of crisis, there may not be a top general with enough power to warn Kim against using a nuclear weapon.