A U.S. surveillance plane was forced to take evasive action after two Chinese fighters intercepted it over the East China Sea, the Pentagon said on Monday.

The incident occurred on Sunday when the two Chinese J-10 warplanes intercepted a U.S. Navy EP-3 reconnaissance plane in international air space west of the Korean Peninsula, Pentagon spokesman Navy Captain Jeff Davis said.

One of the Chinese jets came underneath the U.S. plane at high speed, then slowed and pulled up in front of it, he said. “It was forced to take evasive action to prevent collision,” he said, adding that that it was “uncharacteristic” of the Chinese military. “There are intercepts that occur in international air space regularly, and the vast majority are conducted in a safe manner.”