Amid escalating tensions in the West Philippine Sea (WPS), Armed Forces of the Philippines (AFP) Chief General Romeo Brawner Jr. warned that the death of any Filipino in the contested waters, particularly near Ayungin Shoal (Second Thomas Shoal), would be considered a “red line” that could prompt serious military and diplomatic responses, including potential invocation of the Mutual Defense Treaty (MDT) with the United States.

“If a Filipino dies, that is the red flag, that is the red line,” Brawner told reporters on the sidelines of the second Philippines-Australia Defense Ministers’ Meeting held Friday in Makati City.

Brawner emphasized that the Philippine military has contingency plans in place should the red line be crossed, but declined to disclose specific details, citing operational security concerns.

“But what is clear is that our soldiers will continue to defend the BRP Sierra Madre because it symbolizes our sovereignty.”

The Chinese presence has intensified in recent weeks, with vessels reportedly encircling and attempting to approach the AFP detachment stationed on the shoal.

On 20 to 21 August, the AFP detected a total of 25 vessels, including five China Coast Guard ships, supported by 11 smaller craft, rigid-hulled inflatable boats (RHIBs) and fast boats,  along with aerial support from one rotary-wing aircraft and one unmanned aerial vehicle (UAV).

Some of the fast boats were reportedly armed with mounted weapons, including heavy crew-served guns.

Brawner emphasized that while Filipino troops remain vastly outnumbered and outgunned, they have so far managed to maintain control of the area.

“Our troops have been ordered to exercise maximum tolerance and strictly observe the rule of law,” he said. “Let China be the one to violate international law. We will stay on our post and uphold our sovereign rights.”

The BRP Sierra Madre, grounded on Ayungin Shoal since 1999, is a key symbol of the Philippines’ claim in the area, which lies within the country’s exclusive economic zone (EEZ). The military views its continued presence as a strong assertion of sovereignty in the face of China’s expansive maritime claims.

Asked whether additional troops or reinforcements would be deployed to the shoal, Brawner said the decision rests with the National Task Force for the West Philippine Sea, underscoring the need for a “whole-of-nation approach” in addressing security challenges in the region.

Although the situation remains “tense,” Brawner clarified that no direct skirmishes have occurred so far. “They [Chinese vessels] come close, but our troops continue to push them outward,” he noted.

The Philippines and the US are bound by the 1951 Mutual Defense Treaty, which commits both nations to support each other in case of an armed attack in the Pacific area, including the WPS.

The US has repeatedly reaffirmed that the MDT covers armed attacks on Philippine armed forces, public vessels or aircraft — including those of its Coast Guard — anywhere in the South China Sea.