MANILA, Philippines >> The Philippines charged nine Chinese fishermen Monday with poaching more than 500 endangered sea turtles at a disputed South China Sea shoal despite China’s demand for them to be immediately freed.

Prosecutor Allen Ross Rodriguez said two other arrested Chinese were minors and would be sent home. The nine Chinese have been charged with violating two provisions of the Philippine fisheries code, including illegally harvesting 555 endangered turtles, before a special environmental court in western Palawan province.

Police arrested the fishermen and seized the boat that was allegedly laden with the giant turtles, most of them dead, last week at the disputed Half Moon Shoal. The arrests sparked the latest territorial spat between the Asian neighbors in the increasingly volatile South China Sea.

China has pressed the Philippine government to free the fishermen and the boat, saying they were apprehended in Chinese territorial waters. Beijing warned Manila not to take any more "provocative actions so as to avoid further damage to bilateral relations."

The Department of Foreign Affairs in Manila reiterated that the Chinese were arrested within the Philippines’ exclusive economic zone, the 230 mile (370 kilometer) stretch of sea where the country has exclusive right to fish and exploit undersea gas and oil deposits under the U.N. Convention on the Law of the Sea.

Five Filipino fishermen were caught separately near Half Moon Shoal, about 110 kilometers (70 miles) from Palawan province, with about 70 turtles in their boat. Criminal complaints have also been filed against them for illegally catching the turtles, but they sought the services of Filipino lawyers and were not immediately indicted.

The fishermen face up to 20 years in prison and fines of up to $2,300 each. They can post bail but cannot not leave the Philippines because of immigration law violations after failing to show travel documents.

The turtles recovered alive by police have been returned to the sea, officials said, but TV footages of the dead turtles, some of them apparently butchered and lying in pools of blood on the fishing boat’s deck, have sparked condemnations.

"I don’t think anyone can exaggerate the brutality of what they did," said Jose Ma. Lorenzo Tan, who heads the conservation group World Wildlife Fund in the Philippines. "In a world faced with resource scarcity it makes no sense, no sense at all, for one country to try to gain control of that rapidly depressing resource … because all it is doing is taking the food from someone else."

The shoal, called Banyue Reef in China, is claimed by Beijing as part of the Nansha island chain, known internationally as the Spratly Islands. The Spratlys are a major cluster of potentially oil- and gas-rich islands and reefs long disputed by China, the Philippines, Taiwan, Malaysia, Vietnam and Brunei. China claims virtually the entire South China Sea.

Washington has urged China and the Philippines to resolve the rift diplomatically and voiced concern that the vessels appeared to have been catching endangered species.