North Korea officials "scrapped" the armistice that created nearly 60 years of uneasy peace with South Korea, after the U.N. Security Council unanimously passed tougher sanctions Thursday against Pyongyang for carrying out its third nuclear test.

North Korea also threatened in an editorial in its state-run newspaper:

"As the armistice agreement has been nullified, no one can expect what will happen next."

Is this just your run-of-the-mill saber rattling  or does North Korea's new young leader feel he has something to prove?

President Obama's National Security Adviser Tom Donilon says the U.S. isn't taking any chances.

"The United States will not accept North Korea as a nuclear state. Nor will we stand by while it seeks to develop a nuclear-armed missile that can target the United States," Donilon said.

OutFront tonight: Former  Obama administration National Security Adviser General Jim Jones.