This Philippine Coast Guard handout photo shows China Coast Guard ship 5901, which BRP Cabra spotted off Zambales on Jan. 4, 2025.

MANILA — The Philippine Coast Guard is monitoring Chinese Coast Guard Vessel 5901 — also known as its ‘monster ship’ — after it was detected off Capones Island in Zambales on Saturday.

In an update on Saturday night, Commodore Jay Tarriela, PCG spokesperson on the West Philippine Sea, said the coast guard deployed BRP Cabra (MRRV-4409) and two aircraft after CCG 5901 was detected 54 nautical miles from Capones Island by a Dark Vessel Detection system from Canada.

The PCG confirmed the presence of CCG 5901 by Saturday afternoon and BRP Cabra and the aircraft “continuously challenged the presence of the Chinese Coast Guard, emphasizing that it was operating within the Philippines' Exclusive Economic Zone (EEZ) in accordance with the Philippine Maritime Zones Law and UNCLOS,” he said.

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As of Saturday night, BRP Cabra was monitoring CCG 5901, which was 85 nautical miles from Zambales and heading west.

The 165-meter CCG 5901 dwarfs the PCG’s biggest ship — the 96-meter BRP Teresa Magbanua — and had anchored off Escoda Shoal in the West Philippine Sea in July 2024.

Former US Air Force officer Ray Powell, director of maritime transparency initiative Sealight, said then that the deployment of CCG 5901 to project force .

"From a Chinese perspective, it helps them to have more force projected and especially something large like the monster ship helps them to say, 'We have you at a disadvantage so you should have to negotiate more on our terms,'" Powell told ABS-CBN News last July. 

The Philippines and China in July agreed after “frank and constructive discussions” on the situation in the South China Sea to de-escalate tension in the waters.

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That agreement did not prevent incursions and incidents in the West Philippine Sea — the part of the South China Sea within the Philippines' exclusive economic zone and continental shelf.

Tarriela said Saturday that "[t]he PCG remains committed to closely monitoring this Chinese Coast Guard vessel to ensure that Filipino fishermen can operate safely and without harassment within our Exclusive Economic Zone."

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