The Philippines has lodged a protest with Beijing over the “illegal” presence of a Chinese warship off a disputed island in the South China Sea.

Department of Foreign Affairs spokesman Raul Hernandez said Monday that the Philippines denounced the “provocative and illegal presence of Chinese government ships” off Second Thomas Shoal near the contested Spratly Islands, which was occupied by Philippine marine forces.

Three Chinese vessels – one warship and two maritime surveillance vessels – have remained near the reef and islets, known as Ayungin Shoal, since the complaint was filed two weeks ago, Hernandez said.

Dozens of Chinese fishing boats were also sighted nearby, reports The Associated Press.

Defense Secretary Voltaire Gazmin says another protest might be lodged if authorities can confirm that two ships which chased a Philippine official’s ferry boat last week near Ayungin were Chinese vessels, according to AP.

Philippine marines have been garrisoned at Ayungin Shoal since the mid-1990s. The islet is very close to Mischief Reef, which the Philippines controlled until China built structures on it.