The Philippines on Monday said China deliberately caused collisions between the two countries' vessels in the South China Sea.

"Chinese coast guard and maritime militia vessels, in blatant violation of international law, harassed and intentionally hit Unaiza May 2 and Philippine Coast Guard vessel BRP Cabra," Philippine Defense Secretary Gilbert Teodoro said.

It's a step up in the war of words after two incidents between Philippine and Chinese vessels in the South China Sea on Sunday.

In one of the incidents, China's coastguard said there had been a "slight collision" between one of its ships and the Philippine boat while the coastguard was "lawfully" blocking the boat from transporting "illegal construction materials" to the warship.

In another incident during the same resupply mission, it said a Philippine coastguard vessel's port side was bumped by a Chinese maritime militia vessel.

A Chinese foreign ministry spokesperson, Mao Ning, on Monday urged the Philippines to take Beijing's concerns seriously, stop dangerous maneuvers and stop creating more tension in the South China Sea.

Philippine President Ferdinand Marcos met with security officials and ordered the coastguard to investigate the incidents.

Diplomatic protest

Earlier Monday, Manila summoned Beijing's ambassador and filed a diplomatic protest.

"We're making full use of diplomatic processes... available to us. That includes summoning the Chinese ambassador, which we did this morning," Foreign Ministry spokeswoman Teresita Daza said.

Meanwhile, China's embassy in Manila also lodged a complaint with the Philippines after the collisions, it said in a statement.

Sunday's incidents occurred near the Second Thomas Shoal in the Spratly Islands — a group of largely uninhabited islands in the strategically important sea with various overlapping claims by the Philippines, China, Vietnam, Malaysia and Taiwan.

"Ayungin Shoal is part of our exclusive economic zone and continental shelf and we have sovereign rights and jurisdiction over it," Daza said, using the Philippine name for the shoal that lies around 200 kilometers (124 miles) from the western Philippine island of Palawan — and around 1,000 kilometers from China.

The area has long been a source of dispute but China's increasing presence in the region has stoked tensions to new highs.

Beijing has laid claim to almost the entire South China Sea, ignoring an international ruling from 2016 that there is no legal basis for its claims. 

Trillions of dollars of international trade pass through this maritime region every year.

US and China spar over South China Sea incidents

The United States State Department sided with the Philippines against what it called China's repeated "harassment" in the South China Sea, calling it "unlawful" and "dangerous."

China's coast guard had "violated international law by intentionally interfering with the Philippine vessels' exercise of high seas freedom of navigation," it said in a statement. 

China's foreign ministry said the US "disregarded the facts."

China foreign ministry spokesperson Mao Ning said, "issued a statement in violation of international law, groundlessly attacking and accusing China's legitimate rights and law enforcement actions."

Mao said the Second Thomas Shoal area has always been China's territory.

The US State Department referenced a 2016 arbitration ruling that invalidated China's expansive claims to the South China Sea on historical grounds, including in the Second Thomas Shoal.

lo,ss/ab (AP, AFP, Reuters)