Many experts are already skeptical of North Korea's claims of a successful hydrogen-bomb test

North Korea announced on state television Wednesday that it had successfully detonated a "miniaturized" hydrogen bomb.

The announcement came hours after South Korean officials reported an artificial earthquake 30 miles north of Kilju, where North Korea's primary nuclear test site is located.

The US Geological Survey measured the magnitude of the quake at 5.1, the same magnitude reported after North Korea's most recent confirmed nuclear test, in February 2013.

Despite North Korea's announcement, many geopolitical experts remained skeptical of the country's claims of a successful hydrogen-bomb test, undoubtedly because of North Korean state media's tendency to exaggerate or outright lie about happenings in the isolated nation.

RAND senior defense analyst Bruce Bennett wrote in an opinion piece for CNN that it was unlikely that North Korea had achieved a successful hydrogen fusion bomb considering that the country's three previous nuclear tests appeared to show a difficulty in mastering a fission weapon.

Bennett did note that there was another possibility:

That possibility was echoed by Joe Cirincione, the president of Ploughshares Fund, a global security foundation:

Other experts on Twitter expressed skepticism as well:

Others are noting the similarities in some measures between a 2013 nuclear test and Tuesday's:

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Here's North Korea's full statement, translated to English by NPR:

Chosun's first hydrogen bomb testing was completely successful.

The tens of millions of fighters in our nation embraced the battle cry of the Party with hearts full of boiling blood... 

The strategic determination of the Chosun Workers Party has led to the success of our first hydrogen bomb testing on January 6, 10 a.m., Juche 105 (year 2016).

This test, which relied 100% on our wisdom, our technology and our power, we have proved the accuracy of the technological resources behind our newly developed test hydrogen bomb. We have also proves scientifically the power of miniaturized hydrogen bombs.

The experimentation of our test-hydrogen bomb was carried out safety and perfectly, proving absolutely no negative effects on the surrounding natural environment.

This hydrogen bomb testing elevates the level of our nuclear weapons development. The complete success of our historic hydrogen bomb testing has proudly elevated the DPRK to the ranks of nations possessing nuclear weapons. Our people have boasted the dignified spirit of the nation, with the best nuclear restraint.

The hydrogen bomb testing, carried out by our nation, is a defense mechanism to protect the autonomy and survival of the nation from the increasing nuclear threats of the enemy powers, centered around the US, and reliably guarantee the peace and safety of the region.