North Korea launches 'successful' fifth nuclear test

North Korea conducted its fifth nuclear test on Friday, South Korea and Japan said.

According to meteorological agencies who reported a surface-level seismic tremor near the North's known test site, the tremor indicated it was its most powerful yet.

The US Geological Survey and European agencies measured the quake, which was recorded at 1:30am CET, with a magnitude of 5.3.

South Korean President Park Geun-hye called it an act of "self-destruction" showing the "maniacal recklessness" of leader Kim Jong-un who was completely ignoring the world's call to abandon his pursuit of nuclear weapons.

The US warned of "serious consequences".

China's foreign ministry said Beijing was resolutely opposed to the test and urged North Korea to avoid further action that would worsen the situation.

The North said the test had been of a "newly developed nuclear warhead" and that it was now capable of mounting a nuclear device on ballistic rockets.

South Korea's military said the seismic event indicated a blast with a 10-kilotonne yield, still the largest ever conducted by the secretive North, Reuters reported.

Park said the test was a "grave challenge" to the international community that would "only earn more sanctions and isolation" for North Korea.

"Such provocation will further accelerate its path to self-destruction," she said.