The patrols followed announcements by Japan and South Korea that their military planes had flown through the zone unhindered by China.
The tit-for-tat flights between China on one side and South Korea and Japan on the other heightened the tensions over the East China Sea where China and Japan are at loggerheads over islands they both claim.
The airspace in the new zone announced by China last week overlaps a similar zone declared by Japan more than 40 years ago. Both zones are over the islands known as Diaoyu in China and Senkaku in Japan.
China has said that noncommercial aircraft entering the zone without prior notification would face “defensive emergency measures.”
China would take “relevant measures according to different air threats” to defend the country’s airspace, Xinhua reported.
Responding to the situation, the State Department said, “We have urged the Chinese to exercise caution and restraint, and we are consulting with Japan and other affected parties throughout the region.”
Analysts have said that China’s declaration of the new zone is meant to whittle away at Japan’s hold on the islands. But the unexpected move is also seen as another attempt by an increasingly assertive China to establish itself as the dominant regional power, displacing the United States.
China had seemed to be stepping back this week from its original harsh tone, when it said aircraft entering the airspace needed to file flight plans in advance or face the possibility of military action. On Wednesday, a Foreign Ministry spokesman said China would decide on a case-by-case basis how strongly to respond to those who break its rules.
In a further clarification of its original stance, the People’s Liberation Army said Thursday that the new air zone was “not a territorial airspace” and did not mean that China would take immediate military action against aircraft that entered the zone.
At a monthly briefing for Chinese reporters, a spokesman, Yang Yujun, said it was “incorrect” to suggest China would shoot down planes in the zone. On Thursday, Japan’s top government spokesman, Yoshihide Suga, said that the Chinese had not been notified of the Japanese flights, and reported that China had not scrambled its fighter jets to intercept them.
http://www.nytimes.com/2013/11/29/world/asia/japan-south-korea-fly-military-planes-in-zone-set-by-china.html?_r=0