The White House said on Tuesday it does not have confirmation on whether North Korea actually tested a nuclear bomb—as Pyongyang announced it had—and said the United States may never get a conclusive answer.
"This may take some time; it's a complex undertaking," White House spokesman Tony Snow told reporters.
"There is a remote possibility that we'll never be able to determine fully," he acknowledged.
Snow told reporters "unfortunately I can't give you anything" about the nature of the operation or the strength of the test.
But he added: "It does not change our view that this is an act of provocation, nor does it change the view, more importantly, of our partners in the neighbourhood, who view it much the same way."
While the UN Security Council mulled the various courses of action it can take in response to Pyongyang's announcement that it tested a nuclear weapon, Snow spoke of a "new sense of resolution" among US allies, particularly those closest in proximity to North Korea, such as China and South Korea.
"Everybody is on the same page in terms of talking about sanctions," Snow declared.
North Korea announced its first atomic bomb test on Monday, defying efforts to stop the secretive regime from joining the world's nuclear powers.
Pyongyang has repeatedly argued it needs nuclear weapons to deter any attack from the United States, which it fears will try to topple one of the last Communist regimes in the world.