Manila: Satellite images obtained by Reuters confirmed the presence of a structure at the entrance of the hotly disputed Scarborough Shoal in the South China Sea last week, though later imagery suggests it is no longer there.
The Philippines said on Wednesday it was investigating reports about the presence of a new structure on the Scarborough Shoal, which China has at times attempted to block since it seized de facto control of the atoll in 2012.
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Defence Secretary Gilberto Teodoro received raw information about the presence of the structure, he told reporters on the sidelines of the Shangri-La Dialogue - a regional defence forum - in Singapore on Saturday.
Photographs taken on May 27, 29, and 30 show what an analyst at Vantor, a commercial provider of satellite imagery, said was possibly a floating raft or buoy at the opening of the atoll, in addition to a barrier stretching across it in the May 27 and 29 images.
On Tuesday, U.S.-based maritime monitoring group, SeaLight, posted on X satellite imagery taken on May 28 of Scarborough Shoal showing what it described as a "small, reflective object clearly distinguishable on the reef flat near the lagoon entrance."
"Evidence suggests it is a persistent feature rather than a transient optical artifact," SeaLight said, citing its review of additional satellite images.
But it could no longer be seen in a June 1 image taken by Vantor, the first reported evidence that the suspected structure is no longer present there.
China's defence ministry and its embassy in Manila did not immediately respond to requests for comment.
Scarborough, which China calls "Huangyan Dao" is one of Asia's most disputed maritime sites, and some diplomats and analysts fear long-running frictions and confrontations over the atoll could degenerate into armed conflict.
In recent years, Chinese coast guard vessels have clashed frequently with Philippine fishermen around the shoal, which is located close to major shipping lanes and is coveted for its fish stocks and a turquoise lagoon that provides a haven for vessels during storms.
China's military and coast guard carried out patrols in the area on Sunday, just after Philippine and U.S. forces held a five-day maritime exercise in the same waters - the third such drill this year - to strengthen interoperability and maritime security.
A landmark 2016 ruling on various South China Sea issues by the Permanent Court of Arbitration backed Manila, but establishing sovereignty over Scarborough Shoal was outside its scope.
The court said Beijing's blockade there violated international law as it was a traditional fishing ground for several countries, including China, the Philippines and Vietnam.
Last year, China announced the creation of a national nature reserve at the shoal, a move quickly denounced by the Philippines, which described it as a "clear pretext for occupation."
