It is within China's sovereignty to establish air defense identification zones, an official at the Ministry of National Defense reiterated on Thursday.

Ministry spokesman Yang Yujun made the remark at a news conference in response to comments by a senior United States defense official that the US will not recognize an air defense identification zone in the South China Sea.

"It is the right of a sovereign state to establish air defense identification zones. Other countries' indiscreet advice in this regard is not needed," Yang said.

"Whether and when a country sets up (an air defense identification zone) depends on whether it is faced with aerial threats and how big those threats are."

Reuters quoted US Deputy Secretary of Defense Robert Work as saying on Wednesday that his country would not recognize an air defense identification zone in the South China Sea, and that such a zone would be "destabilizing".

Admiral Harry Harris, chief of the US Pacific Command, said on Feb 25 that he found the possibility of China setting up an air defense identification zone in the South China Sea "to be destabilizing and provocative".

Zhang Junshe, a researcher at the PLA Naval Military Studies Research Institute, said he was puzzled by such "overbearing" remarks.

The US was the first country to set up an air defense identification zone, he said, and more than 20 countries have such zones.

Peng Guangqian, a retired PLA major general, said the US is not a country within the South China Sea region, and it is "not qualified to give indiscreet advice" on whether or not China should set up an air defense identification zone.

"Whether China will set up such a zone or not, it will do it according to international law and to maintain regional peace and stability," Peng said.

China announced the setting up of an air defense identification zone in the East China Sea in November 2013.