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,

Malacañang on Tuesday said the Philippines viewed with concern the presence of China's "monster coast guard ship" in the Philippine waters, saying the government is actively challenging such incursions.