The Philippines has deployed air and sea assets of its military and coast guard in its exclusive economic zone to monitor China's largest coast guard vessel, calling the ship's presence an act of Chinese "intimidation, coercion and aggression".
According to the Philippine coast guard, the 165 m (541 ft) long vessel 5901, referred to by the Philippines as "the monster", was 65 to 70 nautical miles off the coast of the province of Zambales on Sunday.
"We have all our assets pointed at this monster ship. The moment it (carries out) any provocative action, it will be met with appropriate response," Jonathan Malaya, spokesperson for the National Security Council told state television on Monday.
China's embassy in Manila did not immediately respond to a request for comment.
Ties between China and U.S. ally the Philippines have soured in the past few years, with spats frequent as Manila, under President Ferdinand Marcos Jr, pushes back at what it sees as aggression by Beijing. China has accused the Philippines of repeated encroachment in its waters.
China claims most of the South China Sea, a key conduit for $3 trillion of annual ship-borne trade, as its own territory, with a massive coast guard presence in and around the EEZs of neighbours Vietnam, the Philippines and Malaysia.
Beijing rejects a 2016 ruling by The Hague-based Permanent Court of Arbitration that said those expansive maritime claims had no legal basis.
According to video shared by the Philippine coast guard, it ordered the Chinese vessel to leave the area, warning it has no authority to operate there. In its radioed response, the Chinese ship said it was conducting law enforcement duties within its jurisdictional waters.
"This is part of China's intimidation, coercion, aggression and deception. They are showcasing their ship to intimidate our fishermen," Malaya said, adding the Philippine maritime presence would be boosted to support fishermen.
