Story highlights South Korea fears Pyongyang preparing another nuclear test

US call for new sanctions "laughable," North Korea says

(CNN) South Korea is "getting ready for the worst case scenario," the country's Defense Ministry said Monday, after North Korea claimed last week to have tested a nuclear warhead.

World leaders have lined up to condemn the blast, which was North Korea's second this year and likely it's most powerful to date. South Korea believes Kim Jong Un is preparing to hit the button on another test.

"We assess that (North Korea) is prepared for a nuclear test in another shaft," Defense Minister Han Min-koo told lawmakers Friday.

His spokesman Moon Sang-gyun, said Monday if another nuclear test happened, it could come from a second or third site at Punggye-ri, where Friday's test took place.

South Korea is also discussing plans to resume propaganda broadcasts on the border from sometime in November, he added.