The Philippines said Chinese Coast Guard personnel aggressively struck one of its navy staff on the head with a wooden baton during an encounter in the Second Thomas Shoal on Monday in which a navy rubber boat was damaged.
Southeast Asian foreign ministers will gather in Manila for high-level meetings this week, with Chinese Foreign Minister Wang Yi also in attendance.
Tensions in the South China Sea are expected to feature in the discussions.
The Armed Forces of the Philippines (AFP) said a Chinese Coast Guard rigid-hull inflatable boat with eight personnel approached to within close range of its grounded warship on the Second Thomas Shoal and took photos and videos.
When two Philippine navy boats moved to drive the Chinese vessel away, its personnel "reacted violently and aggressively by striking Philippine navy personnel with a wooden baton".
In a 25-second video clip released by the Philippine armed forces, one of the eight could be seen hitting a navy crew member in a rubber boat that was close to the Chinese vessel.
"We call on the People's Liberation Army and the China Coast Guard, including their maritime militia, to put a stop to their illegal, coercive, aggressive and deceptive actions within the West Philippine Sea and adhere to the 2016 Arbitral Award that affirms the Philippines' lawful maritime rights under international law," the Philippine military said.
In response, China's Coast Guard accused the Philippine vessels of ignoring repeated warnings, approaching and ramming a Chinese patrol boat in a dangerous manner and said the Philippine personnel were the first to attack.
"Philippine personnel first used paddles, wooden poles and other implements to aggressively attack Chinese law enforcement officers," a statement said, noting the Chinese forces exercised the utmost restraint in the handling by issuing warnings, making manoeuvring operations around the boats and taking proportionate countermeasures.
China's Coast Guard also accused the Philippines of distorting facts and levelling false accusations against China on the incident, demanding "immediate cessation of infringement, provocation and false hype".
In a 49-second video clip released by China's state-backed tabloid Global Times, Chinese officers can be heard shouting "This is the China Coast Guard, please leave immediately" as personnel from both sides wielded paddles and batons during a confrontation.
The foreign ministry in Manila said the "act of violence" against its navy personnel was "unacceptable" and warranted diplomatic action.
The shoal is within the Philippines' 200-nautical-mile exclusive economic zone and is 1300km from mainland China, which refers to it as the Renai Reef.
The Philippines has accused China of disrupting resupply missions to troops on the grounded vessel.
A June 2024 incident also turned violent, with one Filipino sailor losing a thumb.
The 2024 confrontation later led to a provisional understanding with China to allow resupply missions to the grounded ship.
China has denied allegations of aggressive conduct during encounters in the South China Sea and has accused the Philippines of trespassing in its waters.
