China has completed the first phase of construction on Antelope Reef (Lingyang Reef, 羚羊礁) in the Paracel Islands (Xisha Islands, 西沙群島), building an artificial island in the disputed South China Sea that analysts say will form part of its largest military base.Satellite images showed the reclaimed feature — which Taiwan also claims — in outline for the first time, with barges and dredgers having left after at least six months of work in the busy waterway.The completion shows the South China Sea as an increasingly militarized arena of competition between China and the US and its allies.

China has occupied all the Paracel Islands since 1974, when it forced South Vietnamese forces off the islands.

“The northern part of the South China Sea would be particularly important in a Taiwan conflict scenario, so Antelope is ideally placed,” said Ben Lewis, founder of the open-source data platform PLATracker.Construction of buildings had started in the southeast corner of the island, including a helicopter pad, in the July 19 images taken by Vantor, a commercial provider of satellite images.

The Chinese Ministry of National Defense did not immediately respond to a request for comment.China has yet to acknowledge construction of a new military base, while state media have said that Antelope would serve civilian needs such as weather forecasting and scientific research.Regional security analysts and military attaches say it is more likely to strengthen China’s military hold on the northern part of the waterway.The images show a reclaimed island nearly 6km long, with a straight line of coast longer than 3km that some analysts see as a potential runway.A wharf stretching 680m fronts a deep-water harbor, with one Vantor image showing a China Coast Guard ship alongside.In a study published this week, the Washington-based Center for Strategic and International Studies said the first excavation work for a new runway appeared to have already started.Open source intelligence tracker Damien Symon, who first highlighted dredging at the reef on X in early January said he spotted initial signs of work in December last year.Lewis said he believed Antelope Reef could prove to be one of the Chinese military’s most important features in the South China Sea.“I think the importance of the South China Sea and the Southern Theater Command has been elevated in the last year by the Central Military Commission largely as it relates to Taiwan,” Lewis said, referring to China’s top military panel.China’s military planners might feel more comfortable keeping some weapons, such as its H-6 strategic bombers, in the Paracels and closer to the Chinese mainland rather than on the Spratly Islands (Nansha Islands, 南沙群島) — which Taiwan also claims — further south.The construction work was “modest,” Chinese South China Sea academic Ding Duo (丁鐸) said in an opinion piece published in the official China Daily in June.“Rather than militarization, the purpose is peaceful and constructive — making the waters safer for everyone who depends on them,” Ding wrote.The comments mirror China’s previous explanations of its build-up in the Spratlys in waters also claimed by Southeast Asian neighbours Vietnam, the Philippines, Malaysia and Brunei.Woody Island (Yongxing Island, 永興島) in the Paracels has served as the traditional administrative center for China in the South China Sea.Triton Island (Jhongjian Island, 中建島), also in the Paracels, hosts extensive long-range surveillance devices.