The Philippines has accused China's coast guard of harassment, obstruction, and "dangerous manoeuvres" during a naval operation near the Second Thomas Shoal in the South China Sea. In a Tweet, Jay Tarriela, spokesperson for the Philippine coast guard, said that the smaller Philippine vessels had to reduce speed to prevent a collision with the larger Chinese coast guard vessels. Tarriela further expressed alarm at the presence of Chinese navy ships in the area, remarking that it raised “greater concerns.”

The Second Thomas Shoal is a submerged reef over which the Philippines claims sovereignty. The shoal is located inside the Philippines' 200-mile exclusive economic zone. In order to stake their claim, the Philippines has a handful of troops living aboard a rusty World War Two-era American ship that was intentionally grounded in 1999. The Philippine military conducts regular resupply missions for the troops, including in February when it accused China of aggression and directing a "military-grade laser" at its vessels.

China, however, claims sovereignty over almost the entire South China Sea via a "nine-dash line" on its maps that cuts into the exclusive economic zones of Vietnam, the Philippines, Malaysia, Brunei and Indonesia. Vietnam, Malaysia, Brunei and Taiwan also have claims in the area. China has stated that its coast guard were conducting regular operations in what are Chinese waters. The Chinese embassy in Manila did not immediately respond to a request for comment, and the issue was not mentioned at a regular briefing on Wednesday by the foreign ministry in Beijing.

The territorial disputes are ongoing in the South China Sea, with the Philippines and China in contention over the Second Thomas Shoal. The Philippines has accused China of harassment and obstruction of its vessels, with both sides jostling for control of the strategically important feature. The presence of Chinese navy ships in the area has further raised concerns, with the Philippines maintaining its claim to the shoal via troops aboard a grounded US vessel. With multiple countries in the region making claims to sovereignty, the disputes are likely to continue as tensions in the South China Sea remain high.