MANILA — Warning of hazards to navigation, a Philippine government task force on Wednesday said about 250 Chinese vessels were seen this week in the West Philippine Sea, despite Manila's earlier protest against a Chinese flotilla in a reef in the disputed waters.

The Philippines earlier this month lodged a diplomatic protest against some 220 Chinese vessels, believed to be part of a militia, at the Julian Felipe Reef in the West Philippine Sea, the country's exclusive economic zone within the larger South China Sea.

The National Task Force for the West Philippine Sea said routine aerial and maritime patrol on March 29 spotted even more ships around the West Philippine Sea.

Some 44 "Chinese maritime militia" vessels were seen "moored, anchored, and stationary" at the Julian Felipe reef.

In addition, 115 alleged militia vessels were monitored at Kennan Reef, 45 near Pag-asa Islands and 50 more vessels "dispersed" in the Panganiban, Kagitingan and Zamora Reefs, all within the Kalayaan Island Group (KIG) in the West Philippine Sea, said the task force.

It said 4 People’s Liberation Army Navy (PLAN) vessels were also seen at the Panganiban Reef, which forms part of the exclusive economic zone and continental shelf of the Philippines.

Beijing has denied that the earlier Chinese flotilla at Julian Felipe reef was part of an alleged militia. The Chinese Embassy in Manila said they were fishing vessels taking shelter due to “rough sea conditions.” It also insisted that the reef is part of their territory.

But the Philippine task force said it "stands by its observation that these so-called 'fishing' vessels are maritime militia."

"Their build-up and massing formation from Julian Felipe Reef to other areas of the Kalayaan Island Group is hazardous to navigation and safety of life at sea," the task force said in a statement.

"They may be doing illicit activities at night and their lingering (swarming) presence may cause irreparable damage to the marine environment due to marine pollution and destruction of coral reefs. Their swarming also poses a threat to the peaceful exercise of sovereign rights of the Philippines in its EEZ."

The group called on China to "immediately withdraw these vessels flying its flag."

President Rodrigo Duterte has reaffirmed to China's ambassador in Manila, Huang Xilian, that the Philippines had won a landmark arbitration case in 2016, which made clear its sovereign entitlements amid rival claims by China, his spokesman Harry Roque said last week.

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A 2016 ruling by a United Nations-backed court invalidated China's nine-dash line claim to 90 percent of the South China Sea, a strategic waterway through which at least $3.4 trillion of annual trade passes. Brunei, Malaysia, the Philippines, Taiwan and Vietnam have overlapping claims.

The United States, Japan and Canada have expressed alarm about the Chinese boats.

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"The Philippines appreciates the statements of support from its international partners who share common adherence to rules-based order consistent with international law, including the UNCLOS, as affirmed by the 2016 Arbitral Award," said the West Philippine Sea task force.

"Neither the Philippines nor the international community will ever accept China’s assertion of its so-called 'indisputable integrated sovereignty' over almost all of the South China Sea, part of which is the WPS," it added.

China's maritime assertiveness has put Duterte in an awkward spot throughout his presidency because of his praise and controversial embrace of Beijing, with which the Philippines has a long history of mistrust.

Duterte has been sharply criticized at home for his reluctance to speak out against China and instead blaming close ally the United States for creating conflict in the South China Sea.

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— With reports from Jamaine Punzalan, ABS-CBN News; Reuters