AKIPRESS.COM - North Korea said Wednesday it had conducted a powerful hydrogen bomb test, a defiant and surprising move that, if confirmed, would be a huge jump in Pyongyang's quest to improve its still-limited nuclear arsenal.

A television anchor said in a typically propaganda-heavy statement that the North had tested a "miniaturized" hydrogen bomb, elevating the country's "nuclear might to the next level" and providing it with a weapon to defend against the United States and its other enemies, reports AP.

The statement said the test was a "perfect success." South Korea's Defense Ministry said, without elaborating, that it was bolstering its security posture in response.

There has long been skepticism by Washington and nuclear experts on past North Korean claims about H-bombs, which are much more powerful, and much more difficult to make, than atomic bombs. But a confirmed test would be seen as extremely worrying and lead to a strong push for new, tougher sanctions on North Korea at the United Nations. It would also further worsen already abysmal relations between Pyongyang and its neighbors.

North Korean nuclear tests are worrying because each new blast is seen as pushing North Korea's scientists and engineers closer to their goal of building a bomb small enough to place on a missile that can reach the U.S. mainland.

A successful H-bomb test would be a big step for the North. In a hydrogen bomb, radiation from a nuclear fission explosion sets off a fusion reaction responsible for a powerful blast and radioactivity.

North Korea hadn't conducted an atomic explosion since early 2013, and leader Kim Jong Un did not mention the country's nuclear weapons in his New Year's speech. Some outside analysts speculated that Kim was worried about deteriorating ties with China, the North's last major ally, which has shown signs of greater frustration at provocations and a possible willingness to allow strong U.N. sanctions.

Pyongyang says its nuclear weapons program is necessary to defend itself against the United States. North Korea under leader Kim Jong Un has pledged to bolster its nuclear arsenal unless Washington scraps what Pyongyang calls a hostile policy.

Washington sees North Korea's pursuit of nuclear weapons and ballistic missiles as a threat to world security and to its Asian allies, Japan and South Korea.