Observers interpret the presence of the 165-metre vessel near Scarborough Shoal as a warning to Manila about its military ties with the US.

Beijing has repeatedly asserted its jurisdiction over Scarborough Shoal, which lies within Manila’s exclusive economic zone.

Malacañang yesterday expressed concern over the presence of what has been described as a Chinese “monster ship” off the province of Zambales, even as it gave assurance that the latest intrusion into the West Philippine Sea is continuously being challenged.

The world’s largest coast guard ship arrived at the disputed area as China’s navy holds drills to exert air control.

The Philippines has accused a giant Chinese coast guard vessel it dubbed as the “Monster” of maintaining an “illegal presence” in its exclusive economic zone as Beijing ramps up activities in the disputed South China Sea.

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,

Footage appears to show a Chinese Coast Guard (CCG) vessel reportedly trespassing into waters near a Philippine island. The CCG vessel was spotted sailing some 54 miles off the Capones Island in Zambales province on Saturday (4 January).

The Armed Forces of the Philippines (AFP) stressed Tuesday that it will not be deterred in performing its mandate of patrolling our seas and air despite the presence of China Coast Guard (CCG) vessel 5901 within the country’s exclusive economic zone (EEZ).