Chinese Foreign Ministry spokesman Geng Shuang expressed serious concern over the continuation of military exercises by the US and South Korean troops that are simulating drills near the border to attack North Korean targets.
Reacting to reports of two US bombers from Guam military base joining the target practice, he said, "We (have) noted the military exercise is continuing. We (have) reiterated the current situation in the Korean Peninsula is delicate and complicated."
China opposes any side taking action that may aggravate tensions and undermine regional peace stability, Geng said.
"We again urge relevant sides to stay calm and restrained and stop provoking each other and create better atmosphere for dialogue and engagement," he said.
Asked about what would happen if North Korea conducts another nuclear test, Geng said this was a hypothetical question and he would not comment on it.
However, Geng said, "But there is one thing, I want to make it clear if you read closely UN security council (UNSC) resolutions, it clearly states that the UNSC expresses its resolution to take major measures in response to DPRK nuclear tests and launches. The security council has clear regulations."
North Korea has conducted a total of five nuclear tests, in 2006, 2009, 2013 and twice in 2016.
Mercurial North Korean dictator Kim Jong-un so far has refrained from conducting the sixth, reportedly under pressure from China as US President Donald Trump has virtually put the onus on Beijing to prevail on its ally Pyongyang to abandon its nuclear programme.
China in recent months has stopped import of coal from heavily sanctioned North Korea as part of the implementation of the UN sanctions which reportedly had a crippling effect on the North Korean economy.
Geng also denied reports that Chinese Embassy in North Korea has asked its nationals to leave the country and return home in view of the tensions.
"This is a false news. According my information the Chinese embassy in DPRK has never issued a so called alert asking citizens to return home. China-DPRK are close neighbours with normal exchanges," he said.
Asked whether China was worried that any North Korean nuclear test could trigger a volcanic reaction from Changbaishan volcano on the border between the two countries, Geng said "about whether future nuclear tests will lead to volcano eruption -- this is terrifying. But I don't know whether you have scientific grounds for it."
He asked the media to talk to the concerned professional departments to get a reply.