The Chinese coast guard targeted Philippine vessels with water cannon blasts on Sunday and rammed one of them, causing damage and endangering Filipino crew members off a disputed shoal in the South China Sea, just a day after similar hostilities at another contested shoal, Philippine officials said.

The Philippines and its treaty ally, the United States, immediately condemned the latest confrontation near the Second Thomas Shoal, where two Philippine navy-operated supply boats and two Philippine coast guard escort ships had sailed to deliver food and other supplies to Filipino forces in a long-marooned navy ship that serves as a territorial outpost.

“We condemn, once again, China’s latest unprovoked acts of coercion and dangerous maneuvers against a legitimate and routine Philippine rotation and resupply mission to Ayungin Shoal that has put the lives of our people at risk,” a Philippine government task force that deals with the territorial disputes said in a statement, using the Filipino name for the shoal.

The Chinese coast guard’s high-pressure water cannon blasts disabled and severely damaged the engines of the Philippine supply boat M/L Kalayaan, which had to be towed back to the western Philippine province of Palawan, Philippine officials said, adding the action seriously endangered the lives of the crew. One of two Philippine coast guard escort ships, the BRP Cabra, sustained damage to its mast due to the water cannon blast. Another supply boat was rammed by a Chinese coast guard ship but still managed to maneuver away and deliver supplies to Filipino marines at Second Thomas Shoal, they said.

Drone video footage and photographs issued by the Philippine coast guard show two Chinese coast guard ships separately blasting water cannons at close range at BRP Cabra and a smaller supply boat. “The systematic and consistent manner in which the People’s Republic of China carries out these illegal and irresponsible actions puts into question and significant doubt the sincerity of its calls for peaceful dialogue,” it said. “We demand that China demonstrate that it is a responsible and trustworthy member of the international community.”

The Chinese coast guard said it had “implemented controls in accordance with laws and regulations”. The statement gave no details about the measures taken but said the Philippines action “seriously infringed on China’s sovereignty”.

It also claimed a Philippine vessel ignored warnings and in violation of international navigation regulations made a sharp turn in an “unprofessional and dangerous manner” and intentionally collided with a Chinese coast guard ship, causing “scratching”.

“The responsibility lies entirely with the Philippine side,” the coast guard said.

Coast guard spokesperson Gan Yu described China’s actions as “reasonable, legal and professional”, and said such operations would continue unabated. “We sternly warn the Philippines to immediately cease its infringing actions ... and strictly control its provocations on the front line so as not to drop a stone on its own foot,” Gan was quoted as saying on the coast guard’s website.

China’s actions were strongly condemned by foreign diplomats in the Philippines, including the ambassadors from treaty partner the US, the European Union and Japan.

“The US stands with the Philippines and partners in vehemently condemning the PRC’s repeated illegal and dangerous actions against vessels,” US Ambassador MaryKay L. Carlson posted on X, formerly known as Twitter.

China’s ships, which have surrounded the Philippine-occupied Second Thomas Shoal for years, have blocked Philippine coast guard and supply boats in a yearslong effort to take control of the hotly disputed atoll claimed by both nations.

China has rejected all international condemnation and attempts at legal intervention, including a 2016 ruling by a UN-backed arbitration tribunal that invalidated China’s claims, leaving them without any legal basis. China insists it has a legal right to “defend its sovereignty” in keeping with its claim to virtually the entire South China Sea, one of the world’s most crucial waterways for shipping and other maritime activities.

On Saturday, the Chinese coast guard and accompanying ships also trained water cannons at three Philippine fisheries vessels to prevent them from approaching Scarborough Shoal in the disputed waters off the northwestern Philippines.

That caused “significant damage” to the communication and navigation equipment of one of the three Philippine Bureau of Fisheries and Aquatic Resources vessel, Philippine officials said.

They added that suspected militia vessels accompanying Chinese coast guard ships used a long-range acoustic device that could impair hearing, causing “severe temporary discomfort and incapacitation to some Filipino crew”.

In other high seas clashes this year, Chinese coast guard ships used a military-grade laser that caused Filipino crewmen temporary blindness and engaged in dangerous blocking and shadowing maneuvers that caused minor collisions, Philippines officials say. More tensions loom.

“The Philippines will not be deterred from exercising our legal rights over our maritime zones,” the Philippine government task force said.

A flotilla of 40 civilian fishing boats, backed by Philippine coast guard escort ships, initially was en route Sunday to Second Thomas Shoal but decided to proceed first to two Philippine-occupied islets in the South China Sea to deliver Christmas food packs.

From there, organisers will reassess before the flotilla proceeds with a plan to sail along the vicinity of the Second Thomas Shoal, said one of the organizers, Rafaela David, who denounced the latest Chinese action.