WASHINGTON — China was upset that U.S., Japanese and South Korean aircraft patrolled its new air defense zone over the East China Sea and responded in kind.
Reuters reported  that China flew several fighter jets and early warning aircraft in the disputed area, possibly escalating tensions between China and its regional rivals South Korea and Japan.
The U.S., showing solidarity with Japan, sent two B-52 bombers into the airspace earlier this week as a show of force and support to longtime ally Japan. None of the countries informed China of these flyovers, which infuriated the Communist Chinese government.
The new air defense zone, according to Chinese wishes and self-imposed rules, requires all foreign aircraft, military and civilian, to identify themselves to Chinese authorities. The air defense zone covers the disputed island chain  called the Diaoyu by the Chinese and Senkaku by the Japanese, which has led to some incidents in the region such as Chinese jets flying too close  to Japanese airspace.