Beijing: China on Friday slammed North Korea's fifth nuclear test, saying it was "firmly opposed" to it.
The fifth nuclear test by North Korea -- second this year -- is bound to trigger anxiety and concern to its neighbour and adversary South Korea.
"Today, the Democratic People's Republic of Korea, regardless of universal opposition from the international community, conducted another nuclear test, to which the Chinese government is firmly opposed," China's Foreign Ministry said.
China, North Korea's ally, has expressed concern over Pyongyang launching missiles and conducting nuclear tests despite sanctions slapped by the UN.
"We strongly urge the DPRK side to honour the commitment to denuclearisation, abide by the relevant UN security council resolutions and halt any moves that could aggravate the situations," the statement added.
North Korea on Friday said it "successfully" conducted a nuclear test, its fifth and the "most powerful" test so far, Yonhap news agency reported.
The North Korean Central TV Broadcasting Station said the country carried out a nuclear explosion test to check the capacity of a nuclear warhead.
"We will continue to strengthen our capacity to bolster our nuclear force," it said.
An artificial quake of magnitude 5 was detected around 9.30 a.m. at North Korea's main Punggye-ri nuclear test site.
The US Geological Survey said the tremor was a 5.3-magnitude earthquake.
Pyongyang has conducted a series of ballistic missile launches since top North Korean leader Kim Jong-un gave an order on March 15 to test a nuclear warhead and ballistic rockets capable of carrying the warhead "in a short time".