A Chinese military helicopter flew within 10 feet (3 meters) of a Philippine patrol plane over the South China Sea on Tuesday, in what observers said was the second incident of potentially catastrophic behavior by the People’s Liberation Army against foreign aircraft in a week.

A Philippine plane warned a Chinese military helicopter over the South China Sea that it was "flying too close," as tension between the U.S. ally and Beijing soars.

China's military said it had expelled three Philippine aircraft from the disputed Spratly Islands in the Sea on Thursday, marking the latest in a series of dangerous aerial encounters amid heightened bilateral tensions.