N. Korea threatens rival South over U.N. Sanctions

North Korea has threatened physical counter-measures against South Korea over a tightening of UN sanctions against Pyongyang following its recent rocket launch. 

This comes after the US denounced North Korea for threatening a third nuclear test and imposed new sanctions. 

Outgoing Defense Secretary Leon Panetta said that the US was fully prepared for a test from Pyongyang. 

Washington says, satellite images have indicated that North Korea is pressing ahead with its nuclear program.