The coast guard has stepped up law enforcement patrols in the area since the beginning of August, it said in a statement, vowing to “safeguard China’s territorial sovereignty and maritime rights and interests”.

China sent its naval and air forces on “combat readiness” patrols in the waters and airspace around the atoll, the Southern Theatre Command said in a separate statement.

The Philippine embassy in Beijing did not immediately respond to emailed queries about the statements.

A Chinese coast guard vessel was damaged this month in a collision with a Chinese naval vessel near the Scarborough Shoal, in the first known crash between China’s ships there.

China claims almost the entire South China Sea, despite overlapping claims by Brunei, Malaysia, the Philippines and Vietnam.