The Philippine Coast Guard (PCG) said it has monitored and challenged a Chinese research vessel approximately 37 nautical miles off the coast of Sta. Ana, Cagayan, over the weekend.

In a statement Sunday, the PCG spokesperson for the West Philippine Sea (WPS) said the presence of the Chinese research vessel, Xiang Yang Hong 05, was tracked during the agency’s Maritime Domain Awareness (MDA) patrol yesterday to monitor and challenge the Chinese research vessel Xiang Yang Hong 05 operating within the Philippine Exclusive Economic Zone (EEZ).

Tarriela said the PCG aircraft was dispatched to the waters off northern Luzon after the vessel was tracked approximately 37 nautical miles from Sta. Ana, Cagayan.

During the patrol, the Xiang Yang Hong 05 was sighted 14.92 nautical miles from Babuyan Island.

The Philippine aircraft issued radio challenges, but the Chinese vessel failed to respond.

Xiang Yang Hong 05 initially entered the Philippine EEZ on June 7 after departing from Guangdong, China, on June 5. It exited the EEZ on June 9 and spent nearly three weeks conducting marine research in international waters near Guam before re-entering Philippine territory on July 31.

As of this morning, its location was tracked by the Automatic Identification System (AIS) to be about 86 nautical miles off Calayan Island, Cagayan.

The Xiang Yang Hong 05 is a relatively modern vessel in China’s oceanographic fleet and is known to have been converted from a cargo ship. Its operations have drawn attention due to the vessel’s links to China’s broader maritime strategy.

“Historically, the Xiang Yang Hong series has been associated with supporting the People’s Liberation Army Navy (PLAN) operations, dating back to the original vessels that participated in distant-water research and ballistic missile trials during the 1970s and 1980s,” Tarriela noted.

Tarriela said the PCG continues to monitor the Xiang Yang Hong 05's movements.

“The PCG remains committed to monitoring and protecting the nation's maritime jurisdiction, ensuring the safety and security of its waters against foreign vessels engaged in unauthorized and illegal maritime activities,” he stressed.