The Philippine Coast Guard (PCG) on Friday issued a radio challenge against a China Coast Guard (CCG) vessel off the coast of Zambales in the West Philippine Sea. The PCG on Saturday said CCG vessel 3304 was illegally sailing at approximately 70-80 nautical miles off the coast of Zambales.

China’s “monster ship” has left the coastline of Zambales, but another Chinese vessel is heading to the area it vacated, according to PCG.

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.

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.

Malacaang expresses "grave concern" over the presence of China's so-called monster ship off the coast of Zambales, adding that the Philippines is actively challenging its presence.