[BEIJING] China "firmly opposes" North Korea's nuclear test, the foreign ministry of Pyongyang's main diplomatic protector said Friday, after its fifth atomic blast.
Pyongyang's state media said the test had been successful and achieved its goal of being able to fit a miniaturised nuclear warhead on a rocket.
"Today, the DPRK again conducted a nuclear test despite widespread international opposition - the Chinese government firmly opposes this," the ministry in Beijing said in a statement on its website, using the North's official name.
"We strongly urge the DPRK to honour its commitment to denuclearisation, comply with the relevant security council resolutions and stop taking any actions that worsen the situation," it added.
The statement called for the issue to be resolved through six-party talks - the long-stalled negotiations process chaired by China that also brings together the two Koreas, Japan, Russia and the United States.
China's environmental protection ministry activated a contingency plan following the blast, the official news agency Xinhua reported, adding that it was monitoring for radiation on the North Korean border.
Ties between China and the North have become strained in recent years as Pyongyang has pressed ahead with its nuclear tests, and with Kim Jong Un yet to visit Beijing since inheriting power from his father, who died in 2011.