MANILA, Philippines (AP) -- Philippine officials said Monday they received two intimidating radio warnings identified as from the Chinese navy when they flew a Cessna plane close to a Chinese-constructed island in the South China Sea.
Eric Apolonio said the incident happened Jan. 7 when he and other personnel of the Civil Aviation Authority of the Philippines flew to a Philippine-occupied island for an engineering survey for the installation of civil aviation safety equipment on the island.
The island, which the Philippines calls Pag-asa and is home to a small fishing community and Filipino troops, is close to Subi Reef, one of seven reefs in the disputed Spratly archipelago which China has transformed into islands in the last two years using dredged sand.
Chinese officials say they have completed the island building and are now constructing buildings and runways to ensure safe civilian sea travel. They have acknowledged, though, that the islands could also be used militarily, adding that they have the right to build on what they say is Chinese territory.
The United States and governments with rival claims with China in the disputed region, including the Philippines and Vietnam, have expressed alarm over the Chinese construction, saying it raises tensions and threatens regional stability and could violate freedom of navigation and overflight.
As their Cessna approached Pag-asa to land, Apolonio said a message was received over an emergency radio channel warning: "Foreign military aircraft, this is the Chinese navy. You are threatening the security of our station."
The Filipino pilots ignored the warning and continued with the trip since they were flying a civilian plane over what Apolonio said was Philippine territory. After finishing the survey on Pag-asa, known internationally as Thitu island, they left in the plane and later received the same warning message, he said.
Asked if they felt threatened, Apolonio said they were apprehensive because "you'll never know, we can be fired upon."
The Chinese Embassy in Manila did not immediately reply when asked for comment.
Mayor Eugenio Bito-onon, the leader of the community on Pag-asa who flew with Apolonio's team, said the radio warnings were an act of intimidation and illustrated the threat to freedom of flight in the region. He said other civilian and military planes have also been shooed away by the Chinese in the region.
Despite the incident, Apolonio said the government will proceed with plans to install the aviation equipment, which is required by the International Civil Aviation Organization to help ensure the safety of commercial flights. Called the Automatic Dependent Surveillance Broadcast, the equipment helps aircraft determine their positions via satellite navigation and enables them to be tracked.
British Ambassador to Manila Asif Ahmad said Monday that his government would oppose any move that restricts freedom of navigation and overflight in the disputed waters.
"If a British aircraft, civilian or military, was intercepted and not allowed to fly over a space which we regard as international, we will simply ignore it," he told reporters.