A Japanese military patrol plane circled over disputed parts of the South China Sea on Tuesday at the start of an exercise with the Philippine military that has irked China.
According to Japanese and Philippine officials, the Japanese P3-C Orion surveillance plane, with three Filipino guest crew members, flew at 5,000 feet (1,524 m) above the edge of Reed Bank, an energy-rich area that is claimed by both China and the Philippines. It was accompanied by a smaller Philippine patrol aircraft.
The disputed waters are close to the Spratly Islands, which is claimed by Vietnam, the Philippines and some other countries and territories, where China is building a series of man-made islands.
"We practiced search and rescue patterns, which are essential in any humanitarian assistance and disaster response operations," Marine Colonel Jonas Lumawag said at Puerta Princesa International Airport on Palawan island, the operations base for the drill 50 miles (80 km) to the west.
"This is our first time here and also with this kind of activity with the Philippines," Maritime Self Defense Force Commander Hiromi Hamano, head of the Japanese navy contingent, said after the P3-C returned to Palawan.
An aerial photo taken though a glass window of a Philippine military plane shows the alleged on-going land reclamation by China on mischief reef in the Spratly Islands.
Japan's presence in what it considers international waters may be seen by Beijing as tacit support for ownership claims made by the Philippines.
"We hope the relevant parties do not hype up or even create tensions in the region and we hope the parties concerned can do more to contribute to peace and stability in the region, rather than the opposite," Chinese Foreign Ministry spokesman Lu Kang told a daily news briefing.
Japan worries that China's domination in a region through which much of its sea-borne trade passes would isolate it. Tokyo is also locked in a dispute with Beijing over islands in the East China Sea.
China's official Xinhua news agency has previously condemned the two-day search and rescue exercise as Japanese "meddling". China claims about 90 percent of the 3.5 million sq km (1.35 million sq mile) South China Sea, an area it denotes on maps with its so called nine-dash line.
The exercise by Japan and the Philippines comes as Manila conducts separate drills with the United States military that began last week.