© ReutersA South Korean soldier watches a TV report on the suspected North Korean nuclear test.
North Korea is suspected of carrying out its fifth test of a nuclear bomb after a 5.3-magnitude earthquake was recorded near to its test site.
It happened at 9.30am local time on Friday and had a zero depth, with an epicentre 11 miles from Sungjibaegam in the northeastern part of the county.
South Korea's president was holding a National Security Council meeting as the country's military convened a crisis management team.
Japan's Prime Minister Shinzo Abe said that a suspected nuclear test by North Korea could not be tolerated and that Japan would protest strongly to Pyongyang if confirmed.
Meanwhile China's environment ministry said it has begun emergency radiation monitoring along border regions in northeastern China.
Comment: Comment: UpdateRT:
North Korea has confirmed it has conducted its fifth nuclear test, announcing it is now capable of mounting nuclear warheads on ballistic rockets. The statement came just hours after a powerful explosion was reported near the country's secretive nuclear test site.
"The standardization of the nuclear warhead will enable the DPRK [North Korea] to produce at will and as many as it wants a variety of smaller, lighter and diversified nuclear warheads of higher strike power," a statement from Pyongyang, posted on the website of the Korean Central News Agency, reads.
Pyongyang also claimed that no leakage of nuclear material had occurred in the test, and that there was no negative environmental impact.
A video released by North Korea appeared to show a tremor taking place near the test site.
Earlier, a powerful explosion measured 5.3 in magnitude was reported at the site of North Korea's bomb tests by the US Geological Survey (USGS), triggering reports of an apparent nuclear test.
In January this year, North Korea carried out its fourth nuclear test at the Punggye-ri Nuclear Test Site, which was registered as a 5.1-magnitude tremor by seismological organizations.
The latest test appears to be the most powerful one in the history of North Korea's nuclear program, South Korea's Defense Ministry said, adding that the yield of the previous January test was about 6 kilotons. Earlier tests were conducted in 2013 (6-9 kilotons), 2009 (2-4 kilotons) and 2006 (1 kiloton).
I noticed the diamond before the news mentioned nuke tests.. You don't see such a large diamond on that map very often.. or diamonds at all for that matter..