MANILA, Philippines (AP) — The Philippines has protested China’s deployment of what Manila describes as a floating “structure” with personnel on a disputed shoal in the South China Sea, fearing it could be a part of Beijing’s effort to turn the uninhabited atoll into an island base, Philippine officials said Tuesday.

The Department of Foreign Affairs said, without elaborating, that it lodged a protest over China’s latest action on the Scarborough Shoal, which was spotted by the Philippine military and coast guard.