A Philippine Navy serviceman suffered a serious head injury on Monday in a confrontation with China Coast Guard personnel at Second Thomas Shoal in the South China Sea, the latest violent encounter at a reef where the Philippines maintains a military outpost.

The Philippine military said a rigid-hulled inflatable boat carrying eight China Coast Guard personnel, launched from the coast guard vessel 21560, approached close to the BRP Sierra Madre, the grounded navy ship that serves as the outpost, and circled it while taking photographs and video. Two Philippine rubber boats moved to drive it away “calmly and nonconfrontationally,” the military said, at which point the Chinese personnel “reacted violently and aggressively” and struck a serviceman on the head with a wooden baton.

The China Coast Guard gave a different account, saying the Philippines had distorted the facts. It said the Philippine vessel launched two rubber boats that ignored repeated warnings, collided with a Chinese patrol boat and attacked Chinese officers with paddles and poles, and it urged Manila to stop what it called infringements and provocations. The United States criticised what it described as dangerous Chinese conduct.

The outpost at the centre of the dispute is a warship held in place by its own decay. The Sierra Madre, built during the Second World War as a tank landing ship, was deliberately run aground on the shoal by the Philippine government in 1999 to assert a territorial claim. A rotating detachment of marines has been stationed aboard ever since, dependent on resupply runs for food and water, and the vessel — non-operational and visibly corroding — still flies the Philippine flag. China has repeatedly demanded its removal.

The timing puts the incident directly in front of a diplomatic calendar. ASEAN foreign ministers convened in Manila this week, with the Philippines chairing the bloc for 2026, and Chinese and Philippine counterparts are expected to meet during the gathering. Commemorations of the 50th anniversary of the Treaty of Amity and Cooperation are scheduled for July 24.

It is not the first serious injury at the shoal. A confrontation there in June 2024, during a resupply mission, also left a Filipino sailor badly hurt, in what was then the most violent episode of the dispute.