Approving the 'bomb'published at 06:12
North Korea's KCNA state news agency has released this photo saying it shows Kim Jong-un signing an order for the country to conduct a hydrogen bomb test.
Image source, EPASummary
North Korea claims it has conducted its first successful test of a hydrogen bomb as tremor detected close to main nuclear test site
Announcement met with both international condemnation - but also scepticism over whether blast was large enough to have been from H-bomb
South Korean ministers are holding an emergency meeting and the UN Security Council will meet later
All times GMT
Approving the 'bomb'published at 06:12
Image source, EPAJapanese condemnationpublished at 06:03
Japan's PM Shinzo Abe said the test "is a serious threat to our nation's security and absolutely cannot be tolerated. We strongly denounce it".
He said Japan would take a firm response, including with its allies at the UN.
Image source, EPAWarningpublished at 06:02 Greenwich Mean Time 6 January 2016
The warning signs were there a month ago.
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End of twitter postWhite House statementpublished at 05:59
More from the US response: it has said it will "respond appropriately to any and all North Korean provocations".
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End of twitter postEmergency meetingpublished at 05:48
Image source, APImage caption, South Korean foreign ministry officials convened an emergency meeting after the announcement by North Korea.
North Korea trendingpublished at 05:45
Social media is abuzz over the latest happenings from North Korea. The country is trending, external among thousands of internet users on Twitter, Facebook and Chinese microblogging site Weibo.
'Nowhere near'published at 05:44
Rand Corporation senior defence analyst Bruce Bennett told the BBC that the tremor magnitude was "nowhere near" what it should have been if a hydrogen bomb successfully went off. This could mean North Korea had not set off a real hydrogen bomb, or that it did, but the test failed.
Quake patternspublished at 05:43
The US Geological Survey measured the quake at 5.1 magnitude. Japan's meteorological agency said the waves caused by the tremor resembled those generated by a previous nuclear test in 2013.
Image source, ReutersBirthday present?published at 05:35
The reported test comes just before North Korean leader Kim Jong-un's 33rd birthday. North Korea has used big national events before to showcase its military power.
Image source, APChina to respondpublished at 05:31
State media have reported that the Chinese foreign affairs ministry will be holding a press conference on the apparent test. Many commentators will be watching China's reaction to this very closely.
Quake detectedpublished at 05:29
The first indication of a possible test came earlier on Wednesday, with reports of a tremor in north-east North Korea, close to its main nuclear test site. South Korean officials said shortly afterwards they believed it was an "artificial earthquake".
US investigatingpublished at 05:28
The US State Department said it was "are aware of seismic activity on the Korean Peninsula in the vicinity of a known North Korean nuclear test site" and that is had seen North Korea's claims.
It called on North Korea to abide by its international obligations and commitments.
'Clear violation'published at 05:24
If confirmed it would be the fourth time North Korea has tested a nuclear device.
South Korean Vice-Foreign Minister Lim Sung-nam said any test was a "clear violation of Security Council resolutions and a serious challenge to international peace and security".
'Next level'published at 05:18
Welcome to our live coverage following North Korea's announcement that it has carried out a test of a hydrogen bomb.
North Korean state media said the test was "a perfect success" which took its "nuclear might to the next level".