A senator called Wednesday for an inquiry into how the Philippines could strengthen control of its South China Sea territory, as the coast guard released footage from a standoff between Filipino and Chinese ships in disputed waters a day earlier.

The videos showed a convoy of Philippine boats and ships as they manoeuvered past the China Coast Guard while sailing on a resupply mission to a remote military outpost in Ayungin Shoal (Second Thomas Shoal) in the Spratly Islands.

Two Philippine Coast Guard (PCG) ships, the BRP Cabra and BRP Sindangan, escorted the convoy. They had arranged a rendezvous with civilian boats contracted by the military on Monday before setting off for Ayungin Shoal the following day, Commander Jay Tarriela said.

The PCG spokesman challenged Chinese claims that its ships allowed the supply mission to proceed peacefully, and said that when the Philippine ships were within 2.5 nautical miles of reaching the shoal “we experienced dangerous maneuvers by four China Coast Guard vessels backed by four Chinese maritime militia.

“They executed different ways for the Philippine Coast Guard to be separated from the supply boats so that they would be able to prevent (them) from entering the shoal,” Tarriela told reporters.

Also on Wednesday, Sen. Risa Hontiveros alleged that the People’s Republic of China had continued to militarize portions of the West Philippine Sea, despite international condemnation. Manila uses that name for South China Sea waters that lie within its territory.

During a speech in the Senate, Hontiveros called “for an inquiry, in aid of legislation, into further capacitating and empowering the Philippine Coast Guard to enable it to carry out its primary mission of enforcing Philippine law and upholding national sovereignty within the country’s maritime zones, particularly the West Philippine Sea.”

China’s actions, she said, had led to an “unprecedented challenge to the Philippine Coast Guard’s primary mission of enforcing Philippine law, maintaining the country’s sovereignty and upholding vital national interests.

In Beijing on Wednesday, China’s foreign ministry called on the Philippines “to immediately stop any actions that may complicate the situation on the ground.

“Let me stress that in response to what the Philippines did, China Coast Guard took necessary law enforcement action in accordance with the law,” ministry spokesman Wang Wenbin said.

Tuesday’s incident followed one about two weeks ago where the China Coast Guard fired water cannons at the BRP Sierra Madre, a World War II-era ship deliberately run aground by the Philippines to serve as its military outpost in Ayungin Shoal.

The shoal is about 200 km (124 miles) from the western Philippine island of Palawan, and more than 1,000 km (621 miles) from China’s nearest major landmass, Hainan island.

“Now, it has become clear that China has her eye on Ayungin Shoal. The water cannons, the military laser, the removal of a naval gun cover – all these severe provocations were against Philippine vessels making their way to Ayungin,” Hontiveros told the Senate on Wednesday

“China is actively blocking these missions because she does not want any further reinforcement to our most defiant sovereign marker in the West Philippine Sea, the BRP Sierra Madre.”

On Wednesday, Tarriela presented a video that showed a China Coast Guard ship blocking a Philippine Coast Guard ship from entering the shoal.

A second Chinese ship was positioned to intercept the Filipinos in case they got through the first cordon, the video showed.

“There are also other videos that we have showing that our supply boats were being blocked by China Coast Guard vessels and the four Chinese maritime militia,” he said.

“Well, this time our game plan really was to outmaneuver the China Coast Guard vessels … and make sure that the supply boats would be successful in entering the shoal,” Tarriela said.

The Chinese ships issued radio challenges and warnings that said Beijing had “indisputable sovereignty” over the sea region, according to officials. The Chinese ships said they were allowing the Philippine Coast Guard and the supply boats to pass through “in the spirit of humanism.”

“[W]e don’t need permission from the People’s Republic of China and Ayungin Shoal is within our exclusive economic zone. We have the sovereign right over these waters,” Tarriela said. “Secondly, it is not true that they are humane or extended humanitarian assistance.”

Journalists who travelled with the Philippine Coast Guard on Tuesday posted photos of a U.S. Navy P-8 Poseidon patrol and reconnaissance plane flying overhead during the resupply mission.

In Washington on Wednesday, officials at the Pentagon did not immediately respond to a BenarNews request for comment about the flight. On Monday, U.S., Australian and Philippine troops held an air assault drill in Rizal town, in the western island province of Palawan, about 108 nautical miles from Ayungin Shoal.