The Philippines' Bureau of Fisheries and Aquatic Resources reported on May 22 that a government vessel conducting marine research was attacked by China's Coast Guard with water cannons and deliberately collided with, resulting in damage to the vessel and threats to crew safety. The incident occurred around 9:13 AM on May 21, near the Pag-Asa Cays (referred to as Sandy Cay) in the disputed Spratly Islands in the South China Sea.

According to the Philippine Bureau of Fisheries, the Chinese Coast Guard ship 21559 fired water cannons at the Philippine vessel BRP (number MMOV 3002) and collided with it twice, endangering the safety of the personnel on board. This is the first instance of the Chinese Coast Guard using water cannons against a Philippine vessel near Sandy Cay. Despite the attack, the Philippine research team successfully completed sampling at Pag-Asa Cays 1, 2, and 3.

In response, Chinese Foreign Ministry spokesman Mao Ning stated that he was not aware of the details but reiterated that the Chinese Coast Guard always conducts law enforcement according to the law. The long-standing standoff between China and the Philippines in the South China Sea continues, with Beijing claiming sovereignty over almost the entire sea, despite a 2016 ruling from The Hague international arbitration court that declared China's claims lacked legal basis.