The Philippines on Tuesday said two China Coast Guard vessels fired water cannons at a boat chartered by its navy while traveling in the South China Sea, causing damage to the boat's windshield and minor injuries to at least four personnel on board.

Manila said the boat was heading to a Philippine navy outpost on a disputed shoal on a supply mission when it encountered the Chinese vessels. The incident is the latest attempt by Beijing to prevent Philippine ships sailing to the outpost since early last year.

The boat, which was en route with a number of ships to the outpost in the Manila-controlled Second Thomas Shoal, was also involved in a collision with a China Coast Guard vessel.

One of the two Chinese coast guard vessels was also involved in a collision with a Philippine Coast Guard ship, the Philippine authorities said.

While the navy-chartered boat returned to the western Philippine island of Palawan, one other boat carrying supplies was able to reach the outpost.

Beijing said later Tuesday it had lodged a strong protest to Manila over the incidents, saying four Philippine vessels intruded into waters near the shoal without approval from the Chinese government.

The China Coast Guard claimed the Philippine Coast Guard ship "purposefully engaged in a mild collision" and that Manila "must bear full responsibility." Foreign Ministry spokeswoman Mao Ning said Beijing urges Manila to stop its provocations and refrain from taking any actions to complicate the situation at sea.

The China Coast Guard last used water cannons on Philippine ships in December last year. Beijing asserts its claim over almost the entire South China Sea.

The Permanent Court of Arbitration in The Hague in a 2016 ruling invalidated China's sweeping claim to the resource-rich sea. But Beijing has rejected the decision.

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