The Philippines on Friday condemned Chinese maritime officials for what it described as an “unjustified assault” on Vietnamese fishermen in the disputed waters of the South China Sea, contributing to an ongoing conflict over the incident.

Vietnam reported earlier this week that Chinese law enforcement officers had assaulted ten fishermen and confiscated their equipment while they were working near the Paracel Islands, which are under Chinese control but also claimed by Hanoi, which refers to them as Hoang Sa.

China, which asserts dominance over the majority of the busy waterway, stated on Tuesday that the fishermen were illegally present and that measures had been taken to address the situation. The Chinese government did not immediately respond to the Philippines’ remarks.

Recent confrontations between China and the Philippines, a treaty ally of the United States, have heightened tensions in the strategically significant South China Sea, raising concerns of a potential flashpoint between Washington and Beijing. Philippine National Security Adviser Eduardo Ano expressed solidarity with Vietnam on Friday, condemning the “egregious act” that occurred on Sunday.

The application of force against civilians is a clear violation of international law and undermines fundamental human decency, he stated in his remarks.

The Philippines and Vietnam share overlapping territorial claims in the South China Sea; however, both nations agreed in August to enhance cooperation and address their differences through peaceful means. That month, their coastguards conducted their inaugural joint exercises.

In the past year, encounters in the region have increased as Beijing intensifies its claims, while Manila continues its fishing and resupply operations for military personnel stationed at two disputed shoals.

China asserts its sovereignty over nearly the entirety of the South China Sea through a so-called nine-dash line, which encompasses approximately 90% of the area, and has deployed hundreds of coast guard vessels to patrol against competing claimants.

Chinese officials frequently assert that their coast guard operates in a professional and lawful manner to safeguard its territory from intruders.

The United States maintains a mutual defense treaty with the Philippines and has consistently indicated its commitment to defend its ally should the Philippine coast guard or armed forces face any attacks in the South China Sea.

The Philippine foreign ministry expressed its awareness on Friday regarding a “serious incident” involving Vietnamese fishermen and Chinese maritime authorities, highlighting the importance of all parties exercising true self-restraint.