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The U.S. now believes North Korea might have attempted to test components of a hydrogen bomb on January 6, after further review and analysis of the latest intelligence information.

A U.S. official directly familiar with the latest U.S. assessment said there may have been a partial, failed test of some type of components associated with a hydrogen bomb.

The assessment comes after careful examination of the latest intelligence analysis of the test data. But the official emphasized there is no final conclusion.

Immediately following the test earlier this month, White House Press Secretary Josh Earnest said the initial analysis that have been conducted was “not consistent” with a successful hydrogen bomb test.

The U.S. still does not accept North Korea’s claim that it tested a hydrogen bomb, but air sampling conducted after the test has proved inconclusive, the official said. That prompted another look at the seismic data.

That analysis shows the test was conducted more than two times deeper underground than originally assessed – at a depth consistent with what might be needed for a hydrogen bomb.

However, the size of the seismic event and other intelligence indicates it was not likely a fully functioning device. The official said it’s possible the North Koreans believe they conducted a full hydrogen bomb test, but the U.S. believes it was likely only some components, perhaps a detonator, that exploded.