Philippines probes Scarborough Shoal structure seen in satellite images

A set of recent satellite images has revealed a suspected structure at the entrance of the disputed Scarborough Shoal in the South China Sea, though subsequent imagery suggests the object disappeared within days, fuelling fresh scrutiny over China's alleged activities in one of Asia's most contested maritime flashpoints.

Satellite photographs captured on May 27, 29 and 30, and obtained by news agency Reuters, showed what analysts from commercial imagery provider Vantor described as a possible floating raft or buoy positioned near the entrance to the shoal's lagoon. Images taken on May 27 and 29 also appeared to show a barrier-like object stretching across the lagoon opening.

Further raising concerns, US-based maritime monitoring group SeaLight released imagery from May 28 showing what it described as a "small reflective object" on the reef flat near the lagoon entrance. According to the group, analysis indicated the object was likely a persistent feature rather than a temporary optical anomaly.

However, the structure was no longer visible in satellite images captured on June 1, suggesting it may have been removed or relocated. China's Defence Ministry and its embassy in Manila did not immediately comment on the reports.

Scarborough Shoal, known as Huangyan Dao in China and Bajo de Masinloc in the Philippines, is claimed by both countries because of its strategic location, rich fishing grounds and potential oil and gas reserves in the South China Sea. Although a 2016 ruling by the Permanent Court of Arbitration found that China's historical claims and blockade of the shoal violated international law, Beijing rejected the verdict and continues to maintain de facto control over the reef.

The atoll has remained under Chinese control since a 2012 standoff between Chinese and Philippine vessels and has since become a frequent site of confrontations involving Chinese coast guard ships and Filipino fishermen.

The development has prompted an investigation by the Philippines, which said it was verifying reports of the object spotted near the shoal's lagoon entrance. Philippine Defence Secretary Gilberto Teodoro said he had received initial information regarding the structure while attending the Shangri-La Dialogue security forum in Singapore.

The latest sighting follows reports in April that satellite imagery had shown Chinese vessels and a floating barrier positioned across the entrance to the shoal. Analysts at the time viewed the move as part of efforts by Beijing to tighten control over access to the lagoon. Philippine authorities had then said a 352-metre floating barrier was deployed at the entrance.

Scarborough Shoal occupies a strategically significant position near major shipping routes and resource-rich fishing grounds in the South China Sea. The area has become a recurring source of tension between Beijing and Manila, with regional security analysts warning that any miscalculation could escalate into a wider confrontation.

China has also intensified patrols around the shoal following joint maritime exercises conducted by the Philippines and the United States in nearby waters. Beijing continues to assert sweeping claims over most of the South China Sea, claims that overlap with those of several Southeast Asian nations.

While the 2016 international tribunal ruling stated that China's blockade of Scarborough Shoal violated international law because the waters had long served as traditional fishing grounds for multiple countries, the tribunal did not rule on sovereignty over the shoal itself, leaving the territorial dispute unresolved. China has consistently rejected the ruling.

Although the suspected structure has now disappeared from satellite imagery, its brief appearance has renewed attention on Chinese activities at Scarborough Shoal, which remains central to the broader contest for influence and control in the South China Sea.

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