Manila has accused China of using cyanide near a disputed South China Sea atoll, warning that the toxic substance threatens local fish populations and the structural integrity of a critical reef.
Philippine security officials announced Monday that laboratory tests confirmed the presence of cyanide in bottles seized by the Philippine navy last year. The seizure took place near Second Thomas Shoal, a submerged reef in the Spratly Islands.
Officials say the substance could be part of a deliberate effort to sabotage the area. The reef currently supports a grounded Philippine warship used to reinforce Manila's maritime claims.
Threats to food security and stability
Cornelio Valencia, spokesperson for the National Security Council, described the use of the chemical as a targeted strike against local resources.
“We wish to underscore that the use of cyanide in Ayungin Shoal is a form of sabotage that seeks to kill local fish populations, depriving navy personnel of a vital food source,” Valencia told a news conference.
Valencia added that the toxin could damage the reef ecosystem and "ultimately compromise" the stability of the grounded warship.
China's Foreign Ministry rejected the allegations, calling the report a "stunt."
“The Philippine side illegally harassed the Chinese fishing boats conducting normal fishing, grabbed the fishermen’s living supplies, and staged this so-called cyanide stunt,” said Chinese spokesperson Guo Jiakun. He added that the Philippine claims have "no credibility whatsoever."
Recent months have seen heightened friction between the two nations. In June 2024, a violent encounter during a resupply mission resulted in a Filipino sailor losing a finger.
In December 2025, the Philippines reported that Chinese coastguard ships used water cannons near Sabina Shoal, injuring three people and damaging two fishing vessels. China continues to deny aggressive conduct and maintains that Philippine vessels are trespassing in its waters.
While high-level talks between the two nations last month explored potential cooperation on oil and gas, the Philippine Foreign Ministry stated that any coastguard cooperation will not include sensitive operational areas. The two sides have not discussed joint patrols.
