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.

While Russia's war against Ukraine and a wavering transatlantic alliance drew the world's attention at this year's Munich Security Conference, sparks also flew over claims in the Sea as debate involving participants representing Beijing and Manila dug into their positions in the region.

The Philippines and Japan pledged to enhance their defense alliance through training exercises, logistical activities, equipment transfers and intelligence sharing on Monday amid China’s assertive moves in the South China Sea.

The South China Sea is an important shipping route that holds significant oil and gas reserves.