China's first landing of a plane on one of its new island runways in the South China Sea shows Beijing's facilities in the disputed region are being completed on schedule and military flights will inevitably follow, foreign officials and analysts said.
China's increasing military presence in the disputed sea could effectively lead to a Beijing-controlled air defence zone, they said, ratcheting up tensions with other claimants and with the United States in one of the world's most volatile areas.
Chinese foreign ministry officials confirmed on Saturday that a test flight by a civilian plane landed on an artificial island built in the Spratlys, the first time Beijing has used a runway in the area.
Vietnam launched a formal diplomatic protest while Philippines Foreign Ministry spokesman Charles Jose said Manila was planning to do the same.
Both have claims to the area that overlap with China.
"That's the fear, that China will be able take control of the South China Sea and it will affect the freedom of navigation and freedom of overflight," Jose told reporters.