China Scrambles Jets for First Time in New Air Zone BEIJING - China scrambled jets on Friday and identified two American 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 that 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 that 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 they were coming in advance or face military action. 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 conflict, but to begin to show that it had as much claim to the islands as Japan, which has long administered them. But China may have miscalculated in making the move, analysts say, perhaps not expecting such a strong pushback from the United States and China. The American surveillance planes identified by the Chinese jets on Friday were a P-3 and an EP-3, said Col. Shen Jinke, a spokesman for China's Air Force, according to Xinhua, the state-run news agency. The Chinese account said the 10 Japanese aircraft were of three types of military models. It named the E-767, an airborne warning and control system aircraft, the P-3 surveillance aircraft and the F-15 jet fighter, but did not say how many planes of each type. An American EP-3 was involved in a major diplomatic incident between China and the United States in 2001 when it collided with a Chinese jet fighter over the South China Sea. The Chinese pilot was killed, and the American 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." The spokesman 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 in the airspace above the disputed islands. Mr. Qin, the Foreign Ministry spokesman, brushed aside questions about Japanese criticism of China's air defense identification zone, or A.D.I.Z. Would the Japanese side tell other countries, does it have an A.D.I.Z.? Mr. Qin said. Has it negotiated with other countries while it established and enlarged its A.D.I.Z.? How large is its A.D.I.Z.? An American 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 regards 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," Mr. Dutton said.