Satellite imagery captured on May 28 showed an unidentified reflective object at the southern mouth of Scarborough Shoal’s lagoon, setting off a fresh round of scrutiny over one of the most contested spots in the South China Sea. The image, collected by geospatial analytics platform SkyFi, showed something small but conspicuous at the entrance to the reef.

That is why the image is drawing attention now: Philippine officials want to know whether the object is fixed to the reef or floating, because that difference could matter in a place where even minor changes can alter the balance on the water. SeaLight said the object appeared to be less than 10 meters in diameter, or about 32 feet, but it could not tell whether it was anchored in place or drifting like a buoy.

SeaLight also said a linear feature that looked like a floating barrier was visible across the entrance to Scarborough in imagery taken May 27, and it released that assessment on Thursday. That detail matters because China has used barriers in the past to keep local anglers out of the lagoon, turning a narrow opening into another point of control at a reef it has held de facto since a tense 2012 standoff with the Philippines.

Gilberto Teodoro Jr. said he had only seen “raw information” and had not received confirmation about what the object was or what its nature might be. The defense secretary’s caution leaves open the question that now sits at the center of the Philippine review: whether the object is another fixed feature on the reef, or something temporary that does not amount to a new installation.

The Philippine government said efforts to verify the object’s nature and origin were ongoing, and the National Security Council was tasked with leading the investigation. That comes as the Philippine military said on Tuesday it tracked 82 Chinese coast guard and navy vessels inside the country’s exclusive economic zone in May, including 39 around Scarborough Shoal, a pattern that underscores how crowded and volatile the area has become.

Ray Powell said a fixed installation would raise questions about compliance with the 2002 Declaration on the Conduct of Parties in the South China Sea, which calls for self-restraint and avoiding actions that complicate disputes or alter the status quo on contested, uninhabited features. The shoal sits in a sea that carries more than 3 trillion dollars in annual maritime trade, and for Manila the practical question is no longer just what was seen in the imagery, but whether the next step quietly changes the facts on the water.