The United States has called on China to stop harassing Philippine vessels in the disputed South China Sea following a tense encounter between a Chinese coast guard ship and a Philippine patrol ship in the Ayungin Shoal. State Department spokesman Matthew Miller described the incident as a “stark reminder” of China’s “provocative and unsafe conduct” against Philippine vessels in disputed waters. Miller reaffirmed the US commitment to support the Philippines in the South China Sea, warning that any armed attack on Philippine forces, vessels, or aircraft would invoke its mutual defense treaty. The Philippines and the US are allies under the 1951 Mutual Defense Treaty, dictating that they will defend each other if either is attacked. Philippine President Ferdinand Marcos Jr. is set to meet with President Biden during a five-day visit to the United States to discuss social-economic and security cooperation. Marcos urged direct communication between Beijing and Philippine officials to avoid dangerous collisions between vessels in the disputed waters. Furthermore, the Philippine Coast Guard detected over 100 Chinese maritime militia vessels, a People’s Liberation Army Navy corvette class, and two Chinese coast guard vessels in several Philippine-controlled areas from April 18 to 24.