The United States and the Philippines on Monday launched their biggest joint military exercise in 15 years, with a focus on enhancing preparedness in the region.
This year's annual 10-day Balikatan exercise is twice as large as last year's, involving around 11,000 troops from both nations. The expanded drill is part of Washington's Pacific Pathways program, an effort to boost the U.S. military presence in the Pacific in the face of China's rapid territorial expansion in the South China Sea.
China's rapid reclamation activities around seven reefs in the Spratly Islands has alarmed other claimants, including the Philippines and Vietnam.
U.S. President Barack Obama has said Washington is concerned China is using its "sheer size and muscle" to push around smaller nations in the disputed sea.