The Philippines said a huge Chinese coast guard ship widely known as the “Monster” has returned to its exclusive economic zone in the South China Sea, prompting its own coast guard vessel to approach and issue a radio challenge.

The China Coast Guard vessel 5901 has replaced another Chinese vessel within the Philippines’ exclusive economic zone and positioned 97 nautical miles off the coast of Zambales.

The Philippines said Sunday it had deployed a coast guard ship to challenge Chinese patrol boats attempting to "alter the existing status quo" of the disputed South China Sea.He later told reporters Manila had deployed a coast guard ship to the area to challenge the "unlawful" Chinese patrols.

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.

China has deployed its largest coast guard vessel in the waters of Zambales as the Philippine Coast Guard (PCG) successfully pushes away one of its ships, PCG said on Saturday.