BEIJING China's coast guard urged the Philippines on Thursday to stop sending missions to resupply a vessel near a contested shoal in the South China Sea, warning that such "adventurous actions" could trigger unspecified incidents.

The statement followed a series of confrontations and clashes near the atoll, which has become a flashpoint in a stand-off over territorial and maritime claims in the sea where US$3 trillion worth of trade passes annually.

The Chinese authority said the Philippines' had carried out an airdrop for a vessel there on Wednesday, and that its actions were "very likely to cause unforeseen incidents at sea and in the air," without going into further detail.

The Philippine vessel "can manoeuvre and evacuate on its own, and the relevant problem can be easily solved, but the Philippine side gambles on the health and lives of the officers and personnel," Chinese Coast Guard spokesperson Gan Yu said.

There was no immediate comment from the Philippine Coast Guard or the National Security Council on the reported airdrop or the Chinese comments outside office hours on Thursday. The Philippines has said in the past it is mounting missions to resupply fishermen.

The Sabina Shoal is an atoll about 150km (90 miles) from the western Philippine island of Palawan.

The Philippine Coast Guard has accused China of building an artificial island there, a charge dismissed by China.

On Sunday, the Philippines accused China of using "aggressive and dangerous manoeuvres" to block a sea mission to resupply the ship.

China's coast guard said at the time it had taken "control measures" against a vessel that had "illegally" entered the waters and repeatedly approached Chinese ships in a dangerous manner.

Last week, both countries accused each other of ramming vessels and performing dangerous manoeuvres around the same atoll during a Philippine mission to resupply personnel stationed on Flat Island.

Earlier this month, Manila's military said two Chinese aircraft executed a dangerous manoeuvre and dropped flares in the path of Manila's air force aircraft conducting a routine patrol over Scarborough Shoal. China disputed that saying it acted in a professional and legal manner.

  - Reuters