China's military said it sent warplanes Thursday to patrol its newly-declared air defense identification zone in the East China Sea, just hours after Japan and South Korea challenged Beijing by flying military planes into the zone.
China's official Xinhua news agency said several fighter jets and early warning aircraft had been sent on what a military spokesman described as defensive air patrols over disputed islands controlled by Tokyo and claimed by Beijing.
The Chinese response raises the stakes in an international standoff over the the uninhabited islands, known as Senkaku in Japan and Diaoyu in China.
Japan, the United States and South Korea have all refused to recognize the Chinese-declared air zone. Earlier this week, the United States, which is obligated by treaty to defend Japan, sought to underscore its position by flying two B-52 bombers over the islands.
The unarmed U.S. flights came two days after the Chinese Defense Ministry warned that all aircraft in the zone must identify themselves and obey all orders from Beijing.
Chinese officials had initially reacted calmly to the U.S. overflights by simply acknowledging them and saying the Chinese military had monitored them without taking action. But that measured response quickly ignited criticism on Chinese micro-blogging sites and in some state media.
Earlier Thursday, Chinese Foreign Ministry Spokesman Qin Gang defended the Chinese airspace declaration, saying airlines from many countries have filed relevant applications for flights in the region.
Beijing has sought to portray the airspace declaration as a move to defend national sovereignty. Officials have also sought to point out that the United States and Japan have their own aerial zones.
The festering dispute is one of several maritime controversies pitting China against Southeast Asian nations, including the Philippines, Vietnam, Brunei and Malaysia.
Beijing has indicated a willingness to negotiate the disputes, but so far has rejected calls for multilateral negotiations. It has sought separate talks with each country.