China is justified not to share the details of its natural gas exploration in the East China Sea with Japan, Chinese Foreign Ministry spokesman Kong Quan said Tuesday.

Kong told a regular press conference that it was unreasonable for Japan to ask for this information from China as the exploration was conducted in China's offshore area.

The two countries had never conducted border demarcation on the disputed East China Sea. Japan once unilaterally announced a median line but never discussed the proposal with China. Therefore, China could neither accept nor acknowledge this median line, Kong said.

To solve the territory dispute, Kong said that both sides should begin peaceful negotiations on a basis of equality and mutual respect to avoid escalating the problem.

"A safe and stable East China Sea is good to both sides," he said.

Kong reiterated China's stance of solving problems through consultation and its policy of "sheltering disputes to seek common exploration" of the vast water area.