North Korean state television reported that scientists had successfully conducted a hydrogen bomb experiment at around 10 a.m. local time. The country has now successfully staged its first test of a more powerful form of nuclear weaponry.

A hydrogen bomb is more powerful than plutonium-based weapons, which is what North Korea used in three previous underground nuclear tests.

This test could massively raise the stakes in the state’s attempt to strengthen its nuclear arsenal as it signals significant progress of its military ambitions.

“Let the world look up to the strong, self-reliant nuclear-armed state,” young leader, Kim Jong Un, wrote in what North Korean state TV displayed as a handwritten note.

If there’s no invasion on our sovereignty we will not use the nuclear weapon,” the North Korean state news agency said.

North Korea has long coveted diplomatic recognition from Washington but sees its nuclear deterrent as crucial to ensuring the survival of its third-generation dictatorship.

But the reported nuclear test drew condemnation abroad, including China and Russia, North Korea’s two main allies.

South Korea denounced the test as a violation of United Nations Security Council resolutions that ban nuclear-weapons development by the North, and South Korean President, Park Geun-Hye, condemned what she described as a “grave provocation” and called for a strong international response.

The announcement triggered swift international condemnation but also skepticism, with experts suggesting the apparent yield was far too low for a thermonuclear device as the magnitude of the latest explosion was the same as a 2013 test of an atomic bomb.

State Department spokesman, John Kirby, said the US couldn’t confirm North Korea’s claims of a nuclear test but is monitoring the situation. “We are aware of seismic activity on the Korean Peninsula in the vicinity of a known North Korean nuclear test site and have seen Pyongyang’s claims of a nuclear test,” Mr. Kirby said.