The Chinese coast guard ships and accompanying vessels blocked the Philippine coast guard and supply vessels off the disputed Second Thomas Shoal and executed dangerous maneuvers that caused two minor collisions between the Chinese ships and two of the Philippine vessels, Philippine officials said.

The BRP Sindangan of the Philippine coast guard had minor structural damage from the collision that happened shortly after dawn. Over an hour later, another Chinese coast guard ship first blocked then collided with a supply boat the Philippine coast guard was escorting, the Philippine officials said.

The supply boat, manned by Filipino navy personnel, was later hit by water cannon blasts from two Chinese coast guard ships. Its windshield shattered, injuring at least four Filipino crew members, according to a statement from the Philippine government task force dealing with territorial disputes.

The task force said the actions by the Chinese was “another attempt to illegally impede or obstruct a routine resupply and rotation mission.”

“China’s latest unprovoked acts of coercion and dangerous maneuvers” against Philippine ships en route to deliver supplies and fresh troops to the Philippine-occupied shoal “put the lives of our people at risk and caused actual injury to Filipinos,” it said.

The Department of Foreign Affairs in Manila summoned China’s deputy ambassador to convey a protest against the Chinese coast guard’s actions, which it said were unacceptable.

Chinese military emphasizes dialogue in South China Sea Chinese military emphasizes dialogue in South China Sea

“The Philippines demands that Chinese vessels leave the vicinity of Ayungin shoal immediately,” the department said in a statement, using the Philippine name for the contested shoal.

A small Philippine marine and navy contingent has kept watch onboard a rusting warship, the BRP Sierra Madre, which has been marooned since the late 1990s in the shallows of the Second Thomas Shoal.

China also claims the shoal lying off the western Philippines and has surrounded the atoll with coast guard, navy and other ships to press its claims and prevent Filipino forces from delivering construction materials to fortify the Sierra Madre in a decades-long standoff.

The shoal has been the site of several tense skirmishes between Chinese and Philippine coast guard ships last year