Commercial satellite imagery shows North Korea could conduct its third nuclear test before the end of the month.

A study published by the Bulletin of the Atomic Scientists said a tunnel had been prepared near the site of two earlier tests in 2006 and 2009, Bloomberg reported.

“It apparently has been under construction since 2009 and significant activity was reported at the tunnel site after the failed April space launch. Technically North Korea could be ready to test within two weeks,” an excerpt from the study said, as quoted by the Guardian newspaper.

The tunnel would be used to contain the nuclear explosion.

The authors of the report are Siegfried Hecker, an expert on North Korea’s nuclear program at Stanford University, and Frank Pabian, a geospatial information analyst at the Los Alamos National Laboratory.

The test would be the first authorized by North Korean leader Kim Jong Un, who took control of the reclusive state after the sudden death of his father in December.

The rocket launched in April flew for a short time before crashing into waters off the Korean peninsula, leaving North Korean authorities red faced.

The two scientists said it was possible that North Korea could test plutonium and highly enriched uranium devices at the same time, UPI reported.

“Two detonations will yield much more technical information than one, and they will be no more damaging politically than if North Korea conducted a single test,” the report said, according to Bloomberg.

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