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.

Australia accused the pilot of a Chinese J-10 fighter of unsafe and unprofessional behavior over the Yellow Sea in May last year by dropping flares in the path of an Australian navy Seahawk helicopter. Australia said the helicopter pilot had to take evasive action to avoid the flares.

The Philippine foreign ministry said on Friday it was "concerned" over what it described as "unsafe manoeuvres" and the use of flares by a Chinese air force plane against an Australian Air Force aircraft in the South China Sea.