Story highlights China responds to the US President-elect's new comments on the 'one China' policy

Editorial in state-run newspaper refers to Donald Trump as a "child"

Beijing (CNN) China has warned that it's "seriously concerned" after President-elect Donald Trump questioned whether the United States should keep its long-standing position that Taiwan is part of "one China."

Trump has signaled a willingness to confront Beijing, and his latest comments in an interview with Fox News suggested that he won't hesitate to anger China until the country comes to the bargaining table on trade and North Korea.

China's response was measured but clear: co-operation with the US "would be out of the question" if Trump doesn't adhere to the 'one China' policy -- a cornerstone of bilateral relations since the establishment of diplomatic ties in the 1970s.

"I want to stress that the Taiwan question has a bearing on China's sovereignty and territorial integrity," Chinese Foreign Ministry spokesman Geng Shuang said.

JUST WATCHED Trump questions 'one China' policy Replay More Videos ... MUST WATCH Trump questions 'one China' policy 00:55

"Adhering to the 'one China' principle is the political bedrock for the development US-China relations. If it is comprised or disrupted, the sound and steady growth of the bilateral relationship, as well as bilateral cooperation in major fields would be out of question."