The Philippines' foreign ministry has undertaken appropriate diplomatic action against ‌China in connection with the "illegal presence" of a floating structure in a disputed atoll, the country's South China Sea task force said on Tuesday.

The task force confirmed the presence of a floating structure measuring 6 by 6 meters and featuring what appeared to be an ‌antenna in the disputed Scarborough Shoal in the South China ​Sea.

"The Philippine government will continue to take appropriate actions consistent with international law and in defense of the country's national interests," it ⁠said in a statement, adding that the protection of Manila's sovereignty and ​jurisdiction "remains a paramount consideration."

The structure, initially spotted at the entrance to the shoal ⁠and later inside its lagoon, appeared to be manned, the task force said, citing the latest images from the armed forces.

The task force did not say when the images ‌were taken, but Defence Secretary Gilberto Teodoro said on the sidelines ​of the Shangri-La Dialogue ‌in Singapore on May 30 that he had received raw information indicating the presence of the structure on ‌the shoal.

The task force said it is closely monitoring developments and assessing the nature, purpose and potential implications of the installation, insisting that Scarborough "is part of ⁠the Philippines and within its maritime ‌zones as recognized by international law."

Satellite ⁠images obtained by Reuters on June 5 confirmed the presence of a structure at the ⁠lagoon's entrance, ⁠but later images showed it was no longer present.

Scarborough is a prime fishing spot located 200 km (124 miles) ‌off the western coast of the country. It is also 874 km from Hainan, China's nearest land mass.

Since 2012, China has maintained constant deployment of coastguard and ‌maritime militia ​ships in the area.

Sovereignty ‌over Scarborough, which China calls Huangyan Island, has not been established, but a 2016 arbitral tribunal ruled largely in favor of the Philippines, saying ​China's blockade of the shoal violated international law and that the area was a traditional fishing ground for several countries.