North Korea's first hydrogen nuclear bomb test has been widely condemned and branded a 'wake-up call' for the international community.
An announcement that the potentially catastrophic device was tested was made on North Korean state TV after a 5.1 magnitude earthquake was detected near its known nuclear test site today.
The nuclear test is the fourth by the isolated country, which is under US and UN sanctions for its nuclear and missile programmes.

ReutersCloud: The test was broadcast on state television

Although North Korea previously carried out tests on nuclear devices in 2006, 2009 and 2013, this marks a significant advance in the isolated state's technological capability.
A statement from North Korea said it would continue to strengthen its nuclear programme in order to protect itself against the 'hostile policies' of the United States.

ReutersLeader: Kim Jong Un has made numerous statements about his country's capabilities

North Korea's state news agency said it will not give up its nuclear programme as long as the US maintained what it called "its stance of aggression".
The device had a yield of about 6 kilotonnes, according to the office of a South Korean lawmaker on the parliamentary intelligence committee - roughly the same size as the North's last test, which was equivalent to 6-7 kilotonnes of TNT.
But doubts have been raised over the exact nature of the device.

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Approved:Kim Jong-Un signing a document in Pyongyang for a hydrogen bomb test

"Given the scale, it is hard to believe this is a real hydrogen bomb," said Yang Uk, a senior research fellow at the Korea Defence and Security Forum.
"They could have tested some middle stage kind (of device) between an A-bomb and H-bomb, but unless they come up with any clear evidence, it is difficult to trust their claim."

The test followsleader Kim Jong-un's claims last month that the country was in possession of its first H-bomb.
It's the country's second since young leader Kim Jong Un came into power in 2011.
He said his late father and former leader Kim Jong-Il, "turned the DPRK into a powerful nuclear weapons state ready to detonate a self-reliant A-bomb and H-bomb to reliably defend its sovereignty and the dignity of the nation."



Tremor: The test triggered an earthquake

The test has been widely condemned by the international community this morning.
UK Defence Secretary Philip Hammond wrote on Twitter: "If North Korean H-bomb test reports are true, it is a grave breach of #UNSC resolutions & a provocation which I condemn without reservation."