The Philippines and China have accused each other of responsibility for a maritime confrontation near disputed islands in the South China Sea, further escalating tensions in the resource-rich waterway.

The Philippines alleged Chinese maritime forces used water cannon and rammed a Filipino vessel near Thitu Island, locally known as Pag-asa Island, at the weekend, describing the actions as a “clear threat”, its coastguard said.

According to Manila’s coastguard, three vessels were anchored near the island early on Sunday as part of a government program to protect local fishermen when Chinese ships reportedly approached and used water cannon to intimidate them.

An hour later, a Chinese coastguard ship allegedly fired its water cannon directly at a Philippine vessel before ramming its stern, causing minor damage but no injuries, the coastguard said.

China’s coastguard said two Philippine government vessels “illegally entered” waters near Sandy Cay, a coral reef in the northern Thitu Reefs within the Spratly Islands, leading to a collision.

Beijing said a Philippine vessel “dangerously approached” a Chinese coast guard ship, for which it held Manila responsible.

Manila’s authorities vowed to continue operations in the area, emphasising the need to protect Filipino fishermen’s livelihood.

The disputed area, part of the Spratly Islands, has been the site of repeated confrontations between the two nations over the years.

Tensions have heightened recently, particularly over the Scarborough Shoal and other contested regions in the South China Sea, which China claims almost entirely.

Brunei, Indonesia, Malaysia, the Philippines, and Vietnam also assert claims over portions of the waterway, a strategic trade route that facilitates over $US3 trillion in annual ship-borne commerce.