Al-Jazeera reports that despite prior information issued by Pyongang to Washington and Beijing about the coming test, South Korea has still raised the military alert level in the event of further nuclear tests.
The United Nations Security Council will meet on Tuesday in an extraordinary session to discuss and condemn North Korea's actions. It will almost certainly be the needed prelude for additonal sanctions on the secretive state.
If Pyongyang confirms the test, Washington is expected to come out with an official condemnation. While it may not drive fundamental changes in American policy to North Korea, bilateral relations are very likely to enter the freeze until the next administration in 2016, at least.