The Philippine task force on South China Sea issues confirmed the removal of the structure, which Manila had earlier described as a movable platform likely deployed by Chinese research vessels operating in the area.

“While we take note of the removal, we reiterate our principled and unyielding position: Bajo de Masinloc is and will always be an integral part of Philippine territory,” the task force said in a statement, using the Philippine name for the shoal.

The task force said the Philippines possesses “indivisible, incontrovertible and longstanding sovereignty” over the feature, located about 200 kilometers west of the Philippine coast and approximately 874 kilometers from China’s Hainan Island.

Manila further asserted that only the Philippines has the right to construct structures, conduct activities and undertake marine scientific research within the shoal and its territorial waters. It called on foreign entities to comply with international law and refrain from actions that infringe upon Philippine sovereignty.

The platform was first observed near the entrance of the shoal in late May before later being detected inside the lagoon. Philippine authorities said the structure consisted of wooden planks forming a central deck surrounded by cylindrical flotation devices secured around its perimeter.

The Philippines previously lodged a diplomatic protest with Beijing over the platform’s presence, viewing it as part of activities conducted without Manila’s authorization.

China’s Foreign Ministry maintained its claim over the disputed feature, known in China as Huangyan Island. Foreign Ministry spokesperson Lin Jian said on Wednesday that the structure formed part of a program of “comprehensive research” being carried out in the South China Sea.

Lin said the activities were conducted within China’s sovereign rights and that other countries had no authority to interfere.

The episode adds to longstanding tensions between Manila and Beijing over competing territorial claims in the South China Sea, one of the world’s most strategically important waterways.

Relations between the two countries have faced additional strain in recent weeks after China imposed sanctions on Philippine Defense Secretary Gilberto Teodoro and several of his close relatives over what Beijing described as “erroneous remarks” regarding China. Teodoro responded by saying he would continue performing his duties despite what he characterized as Beijing’s “wickedness.”

China has maintained a regular presence of coast guard and maritime militia vessels around Scarborough Shoal since gaining effective control of the area in 2012 following a standoff with the Philippines.

The sovereignty dispute remains unresolved. In 2016, an international arbitral tribunal in The Hague ruled largely in favor of the Philippines, finding that China’s actions around the shoal violated international law and determining that the area constituted a traditional fishing ground used by multiple countries. Beijing has rejected the ruling and continues to assert what it describes as indisputable sovereignty over the shoal and surrounding waters.