Beijing rejected on Wednesday Philippine complaints about Chinese survey vessels operating in Liyue Tan - also known as the Reed Bank - and has lodged a separate complaint about the detention of Chinese workers.
Philippine President Benigno Aquino III said over the weekend that two Chinese survey vessels had been sighted in Liyue Tan. He questioned China's intention and expressed hope this would not lead to increased tension between Manila and Beijing.
Liyue Tan, a part of the Nansha archipelago in the South China Sea, is Chinese territory.
"Survey activities being carried out by Chinese survey ships are appropriate, legal and beyond reproach," the Chinese Foreign Ministry said in a statement faxed to Reuters.
The Philippine's Department of Foreign Affairs spokesman, Charles Jose, said Manila will file a diplomatic protest "as soon as possible" against the so-called latest Chinese incursion on Liyue Tan, the Philippine Daily Inquirer reported.
Jose said Manila was considering other measures to address the issue.
"Aside from filing a protest, we're also exploring other measures that would address the issue," Jose said, declining to elaborate.
Tensions in the South China Sea between the Philippines and China began in 2011 when a Philippine military vessel entered the sea area neighboring Liyue Tan and tried to approach a Chinese fishing boat towing 25 smaller, unoccupied boats. The propeller of the Philippine vessel got tangled in the rope, disconnecting the Chinese fishing vessel from the 25 smaller boats.
Relations between Beijing and Manila have also been strained by the detention of Chinese fishermen who were intercepted in Chinese waters also claimed by the Philippines.
In a separate incident, the Chinese embassy in Manila lodged a complaint about the detention on Tuesday of more than 50 Chinese suspected of working illegally in the country.
In a statement, the embassy demanded that the authorities handle the case swiftly and fairly and treat those detained properly. Philippine's immigration authorities said that the 55 Chinese had been picked up in raids across Manila.
Reuters - China Daily