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.

Naval and air force units of the US, Canada and the Philippines conducted joint drills in the South China Sea amid growing tensions in the region with China, local media reported Thursday.

"All countries are expected to respect freedom of navigation and overflight in and above international sea lines of communication, such as the South China Sea, and to avoid interference in legitimate activities conducted in international waters and airspace," the Department of Foreign Affairs said in a statement.