BEIJING — China scrambled jets on Friday and identified two US surveillance planes and 10 Japanese aircraft in its newly declared air defense zone, the Chinese state news media said. The scrambling of the jets to find foreign aircraft was the first move announced by China showing it was enforcing the zone, which it established last weekend.
Although there was no indication that China’s air force showed any hostile intent, the move ratcheted up tensions in a long-simmering dispute between Japan and China that could lead to a military miscalculation, which some fear could spiral out of control.
The United States, which is bound by treaty to defend Japan if it is attacked, directly entered the fray this week by sending unarmed B-52s into the contested airspace, defying Chinese demands that all aircraft notify the Chinese that they were coming in advance or face possible military action.
On Friday, officials said the Obama administration has decided to tell US commercial airlines to comply with China’s demands to be notified of any flights through the broad swath of international airspace it has claimed as an air defense zone.
Even as the United States continued to send military planes into the zone in defiance of China’s declaration, officials said they expected civilian planes to go along with Beijing’s new demands out of an abundance of caution.
The administration’s decision contrasted with that by Japan’s government, which told its civilian airlines not to abide by the Chinese rules.
The dispute between China and Japan centers on uninhabited islands in the East China Sea. The new air defense zone includes airspace above the islands. Analysts believe that China’s intent in declaring control was not to force a conflict but to try to build a case that it has as much claim to the islands as Japan, which has long administered them.
But China may have miscalculated in making the move, experts say, perhaps not expecting such a strong pushback from the United States and Japan.
In Washington, administration officials confirmed US planes had continued what they called routine training and surveillance flights in the disputed airspace. The officials, who spoke on the condition of anonymity, declined to provide specifics of the US flights Friday, suggesting that they were classified reconnaissance missions.
The Chinese account in Xinhua, the state-run news agency, said the 10 Japanese aircraft included the F-15 jet and surveillance aircraft, although it did not say how many planes of each type had been spotted.
A US surveillance plane was involved in a major diplomatic incident between China and the United States in 2001 when it collided with a Chinese fighter jet over the South China Sea. The Chinese pilot was killed, and the US plane made an emergency landing on Hainan Island in southern China, an accident that badly damaged relations.
On Friday, asked for clarification on China’s intentions regarding the new air zone, the spokesman at the Foreign Ministry, Qin Gang, said, “The Air Defense Identification Zone does not equal territorial airspace, and is not an expansion of a country’s territorial airspace.”
Qin also said, “Aircraft of all countries, including commercial aircraft, carrying out normal flight according to international law, will not be affected.”
Many countries, including the United States and Japan, have air defense zones, but the coordinates of the Chinese zone overlap with parts of the Japanese zone, setting up what defense experts have called a dangerous situation above the disputed islands.
A US expert on such zones said Japanese aircraft would not be deterred from flying in the airspace above the disputed islands, known as the Diaoyu in China and the Senkaku in Japan.
The expert, Peter Dutton, the director of the China Maritime Studies Institute at the Naval War College in Newport, R.I., said that because Japan regarded the airspace above the islands as its own, the country would continue air patrols.
“Japan must continue to enforce its sovereignty or they could lose it to Chinese pressure,” Dutton said.