The United States on Monday joined ally Japan in vowing not to recognize China's declaration of an air defense zone over much of the East China Sea, a move that has sharply escalated tensions.
China and Japan each summoned the other's ambassador after Beijing said Saturday it had established an Air Defense Identification Zone -- which would require aircraft to obey its orders -- over an area that includes islands administered by Japan.
Japanese Prime Minister Shinzo Abe, who has vowed no compromise on sovereignty issues, called on China to "restrain itself" over the move, which put Tokyo's conservative government in rare unison with South Korea and Taiwan.
"I am strongly concerned as it is a profoundly dangerous act that may cause unintended consequences," Abe told parliament.
US President Barack Obama's administration has vowed to defend Japan and said that the islands -- known as the Senkakus in Japanese and the Diaoyus in Chinese -- fall under the US security treaty with its ally, which has been officially pacifist since World War II.
"This announcement from the Chinese government was unnecessarily inflammatory," White House deputy spokesman Josh Earnest told reporters aboard Air Force One.
The US military, which stations more than 70,000 troops in Japan and South Korea, said it would not abide by the "destabilizing" Chinese-imposed zone.
"When we fly into this aerial zone, we will not register a flight plan, we will not identify our transponder, our radio frequency and our logo. Those are the four things the Chinese have publicly said are a requirement," Pentagon spokesman Colonel Steve Warren told reporters.
"We will not in any way change how we conduct our operations as a result of this new policy," he said.
Japan also said that it would not respect the Chinese demarcation, with a foreign ministry statement saying the move had "no validity whatsoever in Japan."
But an official at Japan Airlines said that the carrier received a notice and would start submitting flight plans to Chinese authorities.
All Nippon Airways, which like its rival considers Asian flights a core part of its business, is following suit, the Jiji Press news agency reported.
The East China Sea dispute has simmered for decades but heated up in September 2012 when Japan nationalized three of the islands, in what it billed as an attempt to avoid a more inflammatory step by a nationalist politician.
Asia's two largest economies now play an almost permanent game of cat and mouse in the area, with official ships and aircraft shadowing each other.
Newspapers in China, where Japan is often portrayed as the villain due to its occupation in the early 20th century, rejected Tokyo's outrage.
"Tokyo is hypocritical and impudent in its complaint with Beijing," said an editorial in the Global Times newspaper, which is close to China's ruling Communist Party.
"If Japan sends warplanes to 'intercept' China's jet fighters, Beijing's armed forces will be bound to adopt defensive emergency measures," it said.
Patrick Cronin, an expert on Asia at the Center for a New American Security, said that China was hoping to set off the "natural proclivities" of both the conservative Abe and the left-leaning Obama.
"China is taunting Japan to act in an incendiary manner while pressing the United States to exercise caution and restrain its ally," Cronin wrote in an essay.
China, which has rapidly expanded its military as its economy soared over the past two decades, also has territorial feuds with other neighbors including the Philippines and Vietnam.
China's declaration of the air zone angered South Korea, which has tense relations with Japan linked to historical memories and just days ago had upset Tokyo by cooperating with China to erect a statue of a Korean activist who assassinated a Japanese governor in 1909.
Part of the air zone overlaps South Korea's own air defense area and incorporates a disputed, submerged South Korean-controlled rock -- known as Ieodo -- that has long been a sore point with Beijing.
Taiwan, which is claimed by China but has been reconciling in the past few years, also complained and vowed to "defend its sovereignty" over the islands.