China's largest Coast Guard vessel has begun to sail away from the waters off Zambales after loitering there for four days, only to be replaced by another Chinese ship in what authorities call a calculated move to maintain Beijing's illegal presence in the area.

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 on Tuesday said it views with alarm the presence of China’s largest coast guard ship within its exclusive economic zone (EEZ), vowing to continue sea patrols. “We view it with concern,

MANILA: China’s “monster ship” has left the coastline of Zambales, but another Chinese vessel is heading to the area it vacated, according to the Philippine Coast Guard (PCG).

A Chinese navy helicopter hovered over a Philippine Coast Guard (PCG) vessel as China's monster ship lingered in Philippine waters. Footage shows the People's Liberation Army-Navy (PLA-N) aircraft with tail number 47 circling above the PCG BRP Cabra monitoring the gargantuan China Coast Guard (CCG) vessel 5901 some 70 nautical miles off Zambales province on January 7.

The PCG has been monitoring the "monster ship" since last Saturday, when it was spotted by the Dark Vessel Detection system 54 nautical miles off Capones Island in Zambales.

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