The Philippines said the China Coast Guard blocked a Filipino supply vessel and damaged it with water cannon on Saturday, causing injuries near a reef off the Southeast Asian country.

The Philippine military released video of what it said was a nearly hour-long attack off Second Thomas Shoal in the contested South China Sea, where Chinese ships have unleashed water cannon and collided with Filipino vessels in similar stand-offs in recent months.

China Coast Guard and other vessels "once again harassed, blocked, deployed water cannons, and executed dangerous manoeuvres" against a routine rotation and resupply mission to the shoal Saturday morning, the National Task Force for the West Philippine Sea said.

"Their reckless and dangerous actions culminated with the water cannoning of UM4 causing severe damage to the vessel and injuries to Filipinos onboard," it said in a statement, referring to the supply boat Unaizah May 4.

The task force did not say how many people on the boat were injured nor identify them or describe their injuries.

China claims almost the entire South China Sea, brushing off rival claims from other countries including the Philippines and an international ruling that its assertion has no legal basis.

Despite the attack, the task force said the damaged vessel and a coast guard escort ship that came to its aid later deployed rigid-hull inflatable boats to deliver its cargo and personnel to the Filipino outpost.

The Philippine soldiers stationed on the shoal live on a derelict navy ship, the BRP Sierra Madre, and require frequent resupplies for food, water and other necessities as well as transport for personnel rotations.

China Coast Guard spokesman Gan Yu said in a statement that the Philippine resupply ship "tried to forcefully intrude into the adjacent waters of Ren'ai Jiao", using the Chinese name for the Second Thomas Shoal, despite the Chinese side's repeated warnings and route controls.

The China Coast Guard carried out "lawful regulation, interception and expulsion in a reasonable and professional manner", Gan said, adding that Philippine ships had attempted to "transport construction materials" to the BRP Sierra Madre.

"We warn the Philippines that playing with fire is an invitation of disgrace, and the China Coast Guard is ready at all times to defend the country's territorial sovereignty and maritime rights and interests," Gan said.

'Impeded and encircled' 

The Philippine task force said the country "will not be deterred -- by veiled threats or hostility -- from exercising our legal rights over our maritime zones, including Ayungin (Second Thomas) Shoal which forms part of our (exclusive economic zone) and continental shelf".

The latest confrontation came four days after visiting Secretary of State Antony Blinken said the United States stood by its "ironclad" commitments to defend longtime ally Manila against armed attack in the South China Sea.

Two days after Blinken's visit to Manila, the China Coast Guard also tried to drive away Filipino scientists who landed on two cays near Scarborough Shoal, another contested South China Sea outcrop.

US ambassador to the Philippines MaryKay Carlson said that Washington stood with Manila against China's "repeated dangerous maneuvers & water cannons to disrupt (the Philippine Coast Guard's) lawful activities in the (Philippine) EEZ".

Carlson also accused Beijing of violating international law and Philippine freedom of navigation in a post on X, formerly Twitter.

The Unaizah May 4 was joined Saturday by an escort of two Filipino coast guard vessels and two Philippine Navy ships, a Philippine military statement said.

The military handout video clips showed a white ship repeatedly dousing another vessel sailing alongside it with a water cannon. One clip showed two white ships simultaneously firing water at the same vessel.

Another clip showed a white ship marked "China Coast Guard" crossing the bow of a grey vessel it identified as the Unaizah May 4.

The vessel was also damaged in a China Coast Guard water cannon attack in the same area on March 5 that left four crew members injured.

The military released yet another video clip which it said showed a Chinese inflatable boat deploying "floating barriers to prevent further entry of any vessels in the shoal".

Another video released by the Philippine Coast Guard showed what it said were three Chinese coast guard and other vessels blocking the BRP Cabra, one of the Unaizah May 4's coast guard escorts.

Apart from supplies and equipment, the Philippine military said six navy personnel were delivered to the BRP Sierra Madre on Saturday, replacing one soldier who was recently evacuated on medical grounds.

The damaged supply boat and its escorts sailed back to port after completing their mission around noon, the task force said.