South China Sea standoff sharpens: blocked resupply and naval drills at disputed shoals

Obstructed resupply to Second Thomas Shoal

The Philippine Coast Guard accused China on Friday of obstructing a resupply mission for Filipino troops stationed aboard a grounded World War II-era warship in the South China Sea, saying the action "put Filipino personnel at risk."

According to Reuters, the Coast Guard said the China Coast Guard and the People's Liberation Army Navy on Thursday "obstructed a legitimate humanitarian and sustainment operation" to Second Thomas Shoal. Manila called China's actions inconsistent with international law and with the 2016 arbitral ruling that invalidated Beijing's sweeping claims in the South China Sea. The Philippines called on China to stop interfering with its lawful resupply missions, and said it would continue its lawful operations and exercise Manila's sovereign rights and jurisdiction in the waterway. The Chinese embassy in Manila did not immediately respond to a request for comment, Reuters reported.

The Philippines has maintained a small detachment of marines aboard the BRP Sierra Madre, a vessel deliberately grounded on the shoal in 1999 to assert Manila's claim. Resupply runs to the ship are the most frequent flashpoint in the dispute. In 2024, Manila and Beijing reached a provisional arrangement on resupply missions to Second Thomas Shoal, which the Philippine foreign ministry has said helped prevent confrontations between the two sides.

This week's obstruction marks another step away from that de-escalation. In July, Manila accused the China Coast Guard of firing water cannon at government vessels near Scarborough Shoal and of striking a Philippine navy staff member with a wooden baton during a separate encounter near Second Thomas Shoal, according to Reuters.

Drills around Scarborough Shoal

Two days later, China's military conducted a joint naval and air training exercise around a disputed shoal in the South China Sea, it said on Sunday. The training was held in the waters and airspace around Scarborough Shoal — which China calls Huangyan Dao and the Philippines knows as Bajo de Masinloc, and which both countries claim.

The PLA Southern Theater Command, in a statement on WeChat, described the operation as a necessary response to actions by "certain countries" it said had undermined regional peace and stability. The military said the training "aims to test and enhance combat capabilities in safeguarding China's territorial sovereignty and maritime rights and interests," according to Reuters. The Philippine embassy in Beijing did not immediately respond to a request for comment about the exercise.

A widening pattern of pressure

Taken together, the two events show Beijing applying military pressure on both of the shoals that anchor the Philippines' position in the northern South China Sea — obstructing Manila's ability to sustain its outpost at Second Thomas Shoal while staging a show of force at Scarborough Shoal, where China has controlled access since 2012.

The pattern extends beyond these two incidents. China's coast guard and maritime militia routinely shadow and block Philippine vessels across the area, and the dispute has drawn in the United States, which has repeatedly reaffirmed that its mutual defence treaty with the Philippines covers attacks on Philippine forces, vessels and aircraft in the South China Sea.

What makes this weekend's sequence notable is the sequencing itself: a civilian-law-enforcement obstruction on Thursday, followed by an overt military exercise at a second contested feature on Sunday. It is the classic two-track approach — the coast guard asserts control in the grey zone while the military signals what stands behind it.

What to watch

Whether the resupply missions continue on schedule will be the near-term test. Under the 2024 provisional arrangement, each mission proceeds without the confrontations that defined 2023 and 2024; Thursday's obstruction, if repeated, would amount to the arrangement's erosion. Also worth watching: whether the Scarborough Shoal exercise was a one-off or the start of a regular pattern of PLA training around features the Philippines claims, and how Manila and its treaty ally respond in the coming weeks.

For background on why these waters matter — and how the dispute connects to the wider contest over the Western Pacific — see our explainer on [why the Taiwan Strait matters](/articles/2026-09-27-why-the-taiwan-strait-matters).