Beijing is using diplomatic go-betweens to press Pyongyang on refraining from conducting another nuclear test, Reuters reported on Monday.
"China has told North Korea that there is no justification for a new nuclear test and that they should not do it," said an anonymous Western diplomatic official who has talked with Chinese officials about the matter.
Multiple China-based diplomatic insiders told Reuters that while Beijing has warned Pyongyang not to conduct a fourth nuclear trial, it has not made any threats of specific punishments that would follow any new underground atomic explosion at the Punggye-ri test site.
"They are against another nuclear test -- but it is a mistake to believe that China is getting more severe," a different source said.
North Korea is already under strong international sanctions. Though Beijing supported the imposition of tougher U.N. Security Council financial penalties in the wake of Pyongyang's 2013 atomic test, the Asian power has since been criticized by some Western nations for not fully enacting the new sanctions.
Pyongyang has made repeated threats that it is ready to carry out a "new" kind of nuclear test. The South Korean government has said it assesses the North to be technically ready to carry out a detonation whenever a political decision is made to do so. Independent foreign observers, however, say that recently detected activity at Punggye-ri could be either in support of an imminent nuclear test or routine maintenance work.