The Philippine Coast Guard (PCG) spotted a Chinese research vessel loitering within the country's exclusive economic zone off the waters of Batanes on Monday morning.

This took place as three People's Liberation Army Navy (PLA-N) warships and one Chinese Coast Guard vessel were monitored operating approximately 31 to 35 nautical miles northwest of Cabra Island, Mindoro Occidental on Sept. 27.

As of Monday afternoon, the PCG had not yet responded to questions if it was the closest intrusion by Chinese vessels in the West Philippines Sea.

Rear Admiral Jay Tarriela, Philippine Coast Guard spokesperson for the West Philippine Sea, said during this morning's maritime domain awareness flight, the Chinese research vessel Jia Hai Ke 7 was monitored at approximately 37.84 nautical miles northwest of Itbayat, Batanes.

"The vessel's behavior is not that of a ship in innocent passage. Rather than steaming on a steady course and speed, Jia Hai Ke 7 has been loitering and holding position in the same area — the movement pattern of a vessel conducting marine scientific research, not transit," he said.

Open source describes Jia Hai Ke 7, a 2,000-ton, 70-meter vessel built for Zhuhai Jiahai Marine Technology Co. as China's first privately owned research ship fitted with a DP-2 dynamic positioning system and quiet electric propulsion which is designed to hold station precisely over a fixed point on the seabed for marine geological survey, and it has operated alongside seabed-drilling ships.

"Its loitering pattern off Itbayat is consistent with exactly this kind of operation," said Tarriela.

He added that the CRV was detected not through its Automatic Identification System (AIS), but by the PCG Monitoring Station in Itbayat.

"The PCG assesses this as deliberate AIS spoofing to conceal the vessel's true movements from Philippine authorities. Without the vigilance of the Itbayat monitoring station, its presence would have gone unnoticed," he said.

"Under SOLAS (International Convention for Safety of Life at Sea), vessels must transmit accurate AIS data at all times; falsifying position data, combined with silence on the radio, points to a vessel that does not want its activity known," he added.

Tarriela noted that "the waters off Batanes and the Luzon Strait host critical submarine cable corridors linking the Philippines to Northeast Asia and the wider Indo-Pacific."

"A seabed-survey vessel hiding its position while holding station in this corridor raises serious concern over the security of the country's undersea communications infrastructure and the potential military use of the data collected," he stated.

According to Tarriela, the PCG challenged the vessel multiple times over the radio, asserting Philippine sovereign rights and demanding that it state its intentions and cease any unauthorized activity. The Chinese vessel did not respond.

"The PCG will continue tracking Jia Hai Ke 7 through its monitoring stations, the DVD system, and follow-on MDA flights, and will take all necessary measures under Philippine law and UNCLOS to challenge and drive away vessels conducting unauthorized activities in our maritime zones," he said.

Based on the verification with the Canada-provided Dark Vessel Detection system, Jia Hai Ke 7 departed Xiamen, Fujian at 12:59 am last Monday (September 21, 2026) and broadcast from off Bindari, Papua New Guinea at 8:10 pm of the same day before it transmit from the Northwest of Itbayat by 6:55 am on Friday. Robina Asido/PHS