China calm in face of US over flight(2)

More than 20 countries, including the US and Japan, set up their own air defense identification zones decades ago.

The US formally defines such a zone in the Code of Federal Regulations, which states: "No person may operate an aircraft into, within, or from a departure point within an ADIZ, unless the person files, activates and closes a flight plan with the appropriate aeronautical facility, or is otherwise authorized by air traffic control."

Xinhua News Agency said in a commentary on Monday, "Japan set up such a zone in the 1960s and it even one-sidedly allowed the zone to cover China's Diaoyu Islands."

Rana Mitter, an expert at Oxford University on Sino-Japanese relations, told Agence France-Presse he feels China's tough stance on issues related to the Diaoyu Islands "clearly regards its own territorial claims as having been underplayed and understated in recent decades and is now looking to reverse the situation".

Taylor Fravel, an expert at Massachusetts Institute of Technology on China's territorial disputes, said the immediate trigger for Beijing's declaration of the zone may have been Japan's threat to shoot down drones after an "unidentified unmanned aerial vehicle" flew toward the islands.

Fravel said China has likely viewed Japan's own zone as being expansive.

Japan's Yomiuri Shimbun newspaper reported on Wednesday that Tokyo has decided to expand its zone. So far, Washington has not objected to the plan.

Zhang said Japan's plan to expand its zone shows it is exercising double standards on the issue.

Li Jie, an expert at the Naval Military Studies Research Institute of the People's Liberation Army, said that by sending the bombers, "the US wants to make sure that its reconnaissance and intelligence gathering on China can continue".

Washington also used the move to show its strength to ensure its status in the Asia-Pacific region, Li said.