The Philippine government is closely monitoring a Chinese fishing research vessel to ensure it does not conduct a maritime survey in Philippine waters, National Security Council Assistant Director General Jonathan Malaya said Thursday.

“It is currently outside the archipelagic waters of the Philippines if I understand it correctly. The Coast Guard is continuing maritime patrol of this vessel to ensure that it keeps to its track and does not conduct a maritime survey inside our waters,” Malaya told reporters in a Palace briefing.

The Philippine Coast Guard (PCG) confirmed that it deployed its aircraft to confront the presence of the Chinese research vessel "Song Hang," which was spotted 58 nautical miles east of Aborlan, Palawan on Wednesday morning.

As of 7:30 a.m. Thursday, the Chinese vessel was approximately 48.65 nautical miles northeast of Tambisan Island in Sabah, Malaysia.

Acknowledging that foreign vessels are entitled to innocent passage under international law, Malaya emphasized that they are not permitted to conduct maritime surveys in Philippine waters.

“Because although ships have the right of innocent passage, no foreign vessel can conduct a maritime survey in our waters,” Malaya said.

He then mentioned that the BRP Malapascua (MRRV-4403) is currently monitoring the Chinese research vessel.

“So, the Philippine Coast Guard is being vigilant. They are continuously doing maritime patrols to ensure that this does not happen,” he said.

According to PCG spokesperson for the West Philippine Sea, Commodore Jay Tarriela, the Chinese fisheries research vessel, Song Hang, was repeatedly radio-challenged by the crew from BRP Malapascua.

In its response to the radio challenge, the Chinese vessel said it was en route to the Indian Ocean to conduct fishing activities.

“Last night, when BRP Malapascua was conducting maritime patrols off the coast of Mapun Island, we were able to do a radio challenge on the Chinese research vessel at a distance of 34.6 nautical miles northeast of Mapun Island,” Tarriela told reporters in a virtual interview on Thursday.

“Unlike yesterday, this CFRV responded to our questions like where it is heading. Ang sabi ng vessel sa radio is that it is proceeding to the Sibutu Passage at pupunta ng Indian Ocean,” he added.

The ship, staffed by 25 Chinese crew members, left Shanghai on March 26.

Tarriela noted that the 85-meter Song Hang is China’s first ocean-going research vessel, which was launched in 2017.

“This morning, BRP Malapascua again conducted a radio challenge on the CFRV… We once again asked the intention of the CFRV. It reiterated its response… ang sabi it is proceeding to the Indian Ocean. What is quite unusual sa response ng isang CFRV, sabi nila, they are going to the Indian Ocean to catch fish,” he said.

As of Thursday noon, the Chinese vessel was monitored 35.5 nautical miles off Mapun Island in Tawi-Tawi.

Tarriela said that the vessel exercised its right to innocent passage, transiting "continuously and expeditiously" through archipelagic waters.

“Pumasok sila ng Mindoro Strait, bumaba at diretso ng Sibutu Passage (They entered the Mindoro Strait, went down, and went straight to the Sibutu Passage). That is basically our archipelagic sea lanes. As far as the movement of the CFRV is concerned, tuluy-tuloy naman at hindi huminto (it was continuous and did not stop),” he said.

Tarriela said the PCG has been closely monitoring and informing the CFRV “that they are not authorized to conduct marine scientific research” in Philippine waters.

“Based on our monitoring, wala naman tayong namataan na nagbaba sila ng gamit whatsoever that we can say na nagkoconduct sila ng MSR (Based on our monitoring, we have not observed any equipment being lowered or anything that would indicate they are conducting MSR),” Tarriela said.

“We haven’t monitored any illegal activities na masasabi natin na (that we can say) they are taking advantage of such right,” he continued.

The Song Hang is expected to leave the Philippines' exclusive economic zone (EEZ) through the Sibutu Passage late Thursday.