The Philippines this week protested the "provocative and illegal presence" of the warship near Second Thomas Shoal, but China brushed off the complaint with an insistence that the area was part of its territory.
Philippine foreign department spokesman Raul Hernandez said today the warship, along with two patrol vessels and a fleet of Chinese fishing boats, remained near the shoal.
"They should not be there. They do not have the right to be there... No-one should doubt the resolve of the Filipino people to defend what is ours in that area," Hernandez said in a text message to AFP.
China claims nearly all of the South China Sea, even waters far away from its main landmass and approaching the coasts of Southeast Asian countries.
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The Philippines, Vietnam, Malaysia, Brunei and Taiwan also claim parts of the sea, and the area has for decades been regarded as a potential trigger for major military conflict in the region.
Second Thomas Shoal is a tiny group of islets and reefs in the Spratly Islands chain, about 200 kilometres (120 miles) northwest of the Philippine island of Palawan, the nearest major landmass.
Second Thomas Shoal is guarded by a handful of Philippine marines aboard a World War II-era ship that was deliberately grounded there in the late 1990s to serve as a base.
It is about 41 kilometres (25 miles) east of Mischief Reef, a Philippine-claimed outcrop that China occupied in 1995.
Second Thomas Shoal and Mischief Reef are within the Philippines' internationally recognised exclusive economic zone, and surrounding waters are rich fishing grounds.
Last year China took control of Scarborough Shoal, another bountiful fishing area far closer to Filipino landmass than Chinese, after a similar stand-off ended with the Philippines retreating.
Philippine President Benigno Aquino this week announced a planned USD 1.8-billion military upgrade to defend the country's maritime territory against "bullies".