The U.S. media is reporting that North Korea's purported nuclear test may have been a failure,
as Washington has yet to confirm the test as of Monday.

Citing initial expert assessments, a U.S. official speaking under condition of anonymity said that the test was close to a failure.

The Associated Press quoted the official as also citing difficulty in confirming whether a seismic wave detected in the North was due to the testing given its relatively low magnitude.

Fox News also quoted a U.S. official as saying the nuclear test, very small in size, failed to deliver Pyongyang's "intended result."

Without officially confirming the test, White House spokesman Tony Snow said only that Washington is analyzing data to clear the facts.