The goverment of the Philippines issued an outraged condemnation Wednesday of a Chinese vessel for sinking a Philippine fishing ship near the Spratly Islands, in sovereign Philippine territory that China illegally claims as its own.

The Philippine Department of Foreign Affairs (DFA) accused the Chinese ship of ramming into the Philippine ship on Sunday near Recto Bank, a submerged feature near the Spratly Islands that the Philippine ship had anchored on. Manila has not offered a definitive statement accusing the Chinese of sinking the ship deliberately but instead lodged a formal protest because the ship fled the scene, leaving the ship’s crew to drown. As the Chinese Communist regime has not commented on the incident, there is no formal confirmation that the ship involved is Chinese, though Beijing has also not denied it.

China claims almost the entirety of the South China Sea, including significant portions of the sovereign territory of the Philippines. It has invaded, colonized, and militarized reefs in the Philippines’ Spratly Islands and disregarded an international legal ruling that declared all its construction in the region illegal.

According to the crew, after six hours, a Vietnamese vessel found and rescued all 22 of them. Jimwel Jimwel Tañedo, the cousin of the captain of the ship, told Philippine television on Wednesday that the incident happened while they were stationary in the water and sleeping, around midnight local time. As they were sleeping, the crew did not have context for what happened, where the Chinese ship came from, or if the ship warned them to get out of the way before ramming into them.

Foreign Affairs Secretary Teodoro Locsin Jr. called the incident a “hit and run” and “fired off a diplomatic protest” at Beijing, he said on Twitter. He added that, while “my people in Manila” expect a friendly and diplomatic approach towards the Chinese Communist Party on the matter, he believed “we can take it a little farther,” without elaborating on what that meant to him.

Philippine Defense Secretary Delfin Lorenzana is calling for a formal investigation to confirm that the Chinese ship abandoned those it sank into the sea and to find conclusive evidence of the Chinese ship’s intentions.

“We thank the captain and crew of the Vietnamese vessel for saving the lives of the 22 Filipino crew. However, we condemn in the strongest terms the cowardly action of the suspected Chinese fishing vessel and its crew for abandoning the Filipino crew,” Lorenzana said in a statement Wednesday. “This is not the expected action from a responsible and friendly people.”

Salvador Panelo, spokesman to President Rodrigo Duterte, had even harsher words for China.

“We will not allow ourselves to be assaulted, to be bullied, to be the subject of such barbaric, uncivilised and outrageous actions from any source,” he told reporters, according to Agence France-Presse (AFP). “We will cut diplomatic relations, that’s what you do whenever there are aggressive acts.”

Duterte’s government is taking the official line that the ramming was an accident until proven otherwise. The Philippine Star quoted a Philippine Armed Forces (AFP) spokesman, however, who described the incident as “far from accidental.”

“If it’s accidental, it’s (Standard Operating Procedure) they should stop, they should rescue these fishermen,” Lieutenant Colonel Stephen Penetrante said.

The sinking of a Philippine ship is unprecedented in the modern history of the South China Sea dispute, according to experts who spoke to the Philippine news outlet Rappler. It is not the first such sinking by China, however, or the first incident of harassment targeting Philippine fisherman. In the former category are several sinkings of Vietnamese vessels in recent memory. Chinese ships have attacked and sunk at least two Vietnamese vessels, one in 2014 and one in 2015, in the last decade in the region.

China has been on a targeted harassment campaign against the Philippines, however, since the country won a lawsuit at the Permanent Court of Arbitration at the Hague against China in 2016. Philippine officials have complained that China has jammed ships’ radio signals; stolen Philippine fishing catches; harassed Philippine ships out of their sovereign territory; and flooded parts of the Philippines with “fishing vessels” that experts believe are disguised paramilitary units meant to intimidate locals out of using their waters.

China claims territory belonging to the Philippines, Vietnam, Taiwan, Brunei, Malaysia, and Indonesia in the South China Sea, the last of these only the waters surrounding Natuna Island. Chinese officials routinely argue that the sea has been under Chinese control since “ancient” times, but have not provided viable evidence for this claim, in 2016, the Hague court found that China’s constructions in international and foreign waters were illegal, and ordered it to vacate the territory.

China has ignored the ruling entirely and found in Philippine President Duterte an unwilling challenger. Duterte has insisted against confrontation with China, despite overwhelming popular support for defending national sovereignty, and joked that China is seeking to make the Philippines its “province.” Among the few actions against the Chinese Duterte has taken is to reluctantly sue the government for illegal clam harvesting in Philippine waters in April.

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