The Philippines on Tuesday summoned the Chinese ambassador to protest against China's plans to establish a military garrison on the disputed Paracel Islands in the South China Sea.
The foreign department said it summoned Ma Keqing to lodge the complaint, and also to object to the arrival of a military-escorted Chinese fishing fleet near the contested Spratly Islands.
The Chinese defence ministry announced plans to operate troops from Chinese-held Sansha or Woody Island in the Paracels on Monday, a month after Beijing designated the island as China's administrative centre for both the Paracel and Spratly groups.
While the Philippines does not have territorial claims on the Paracels, foreign department spokesman Raul Hernandez said the Chinese plan to administer both island groups from Sansha was unacceptable.
"The Philippine government has expressed its grave concern and registered its strong protest over the Chinese government decision to establish a military garrison in Woody Reef," Hernandez told reporters.
China claims sovereignty over nearly all of the South China Sea, which is believed to hold vast amounts of oil and gas, while the Philippines, Taiwan, Brunei, Malaysia and Vietnam each claim portions.
Disputes have flared in recent weeks, with Vietnam and the Philippines criticising what they call Chinese encroachment.
China and South Vietnam once administered different parts of the Paracels but after a brief conflict in 1974, Beijing took control of the islands.
The Philippine foreign department said it summoned the Chinese ambassador over the garrison plans as well as to receive a strong objection to China's dispatch of a military-backed fishing fleet in Spratly waters.
The Filipino coast guard monitored a fleet of 29 fishing vessels, a cargo vessel, and three other ships including one Chinese navy vessel near Fiery Cross Reef and Subi Reef on July 18, Hernandez said.
"The use of armed government vessels to escort fishing vessels that conduct non-fishing activities is a violation of Philippine territory and a violation of obligation of states under international law," Hernandez said.