Two armed Chinese J-10 fighter jets performed what U.S. Defense officials are qualifying as an “unsafe” intercept of an American EP-3 reconnaissance aircraft on Sunday.  The interaction between the two planes took place over what the United States considers to be the international waters of the East China Sea, in an area described as west of the Korean peninsula.

China maintains an “Air Defense Identification Zone” over the vast majority of the East and South China Seas, and has continued to make claims of sovereignty over the highly trafficked waterways.  The United States does not recognize their claims as legitimate.

One of the two J-10s approached the unarmed U.S. aircraft from beneath it at a high rate of speed, before slowing and pulling up into the flight path of the American aircraft.  The U.S. EP-3’s collision avoidance system was triggered by the J-10, forcing the American pilot to take quick evasive action to avoid the Chinese jet.

“This is uncharacteristic of the normal safe behavior we see from the Chinese military,” said Navy Capt. Jeff Davis, Pentagon spokesman. “There are intercepts that occur in international airspace regularly, and the vast majority of them are conducted in a safe manner. This was the exception, not the norm.”

Navy Lt. Cmdr. Matt Knight, a spokesman for U.S. Pacific Fleet in Hawaii, said the EP-3 was conducting routine operations in international airspace when the intercept occurred.

“While we are still investigating the incident, initial reports from the U.S. aircrew characterized the intercept as unsafe,” Knight said. “The issue is being addressed with China through appropriate diplomatic and military channels.”

China, on the other hand, have characterized their aircraft’s behavior as “legal, necessary, and professional.”  They also claimed their intercept was conducted “in accordance with the law and the rules.”

“Close-in reconnaissance by U.S. aircraft threatens China’s national security, harms Sino-U.S. maritime and air military safety, endangers the personal safety of both sides’ pilots and is the root cause of unexpected incidents,” China’s Defense Ministry said in an official statement.