The Philippine Coast Guard (PCG) on Wednesday said a Chinese floating structure previously spotted near the entrance of Bajo de Masinloc has been relocated inside the disputed shoal's lagoon, prompting continued monitoring by Philippine authorities.

Speaking during a National Task Force for the West Philippine Sea (NTF-WPS) briefing in Manila, PCG spokesperson for the West Philippine Sea Commodore Jay Tarriela said the movement of the structure was observed on 31 May and was supported by two boats.

The PCG also reported the presence of a buoy, an unidentified floating object and an antenna structure in the vicinity of the shoal.

Tarriela presented photographs taken during a recent maritime domain awareness flight showing the floating structure inside the lagoon of Bajo de Masinloc, also known internationally as Scarborough Shoal.

He said the first indication of the structure was detected through satellite imagery on 25 May. A maritime domain awareness flight by the Bureau of Fisheries and Aquatic Resources verified its presence near the southeast entrance of the shoal on 26 May, while a PCG flight confirmed the sighting on 28 May.

The PCG also monitored a People's Liberation Army helicopter operating near the shoal during the same period. On 29 May, authorities observed a buoy on the northern portion of the shoal and two Chinese vessels operating inside the area.

A subsequent PCG flight on 30 May spotted six individuals aboard the floating structure and a newly installed antenna on a rock near the entrance of the shoal. Tarriela said a People's Liberation Army fighter jet intercepted the Philippine aircraft during the mission.

On Tuesday, the Department of Foreign Affairs announced that it had filed a formal diplomatic protest against China over the presence of the floating structure near Bajo de Masinloc, the site of repeated maritime confrontations in the West Philippine Sea.

Bajo de Masinloc is located about 240 kilometers west of Luzon and nearly 900 kilometers from China's Hainan Island. Although China claims almost the entire South China Sea, an international arbitral tribunal ruled in 2016 that Beijing's expansive claims have no legal basis under international law.

Meanwhile, Armed Forces of the Philippines (AFP) spokesperson for the West Philippine Sea Rear Admiral Roy Vincent Trinidad said the military continues to sustain maritime security operations and strengthen cooperation with partner navies.

From 1 May to 9 June 2026, the Northern Luzon Command, through the Northern Luzon Naval Command, conducted 42 maritime patrol and air surveillance missions, including 35 maritime patrols and seven air surveillance flights.

The Philippine Navy also carried out six maritime cooperative activities within Philippine waters, consisting of three bilateral and three multilateral exercises with partner navies.

Trinidad said the activities enhanced interoperability, strengthened coordination mechanisms and improved the participating forces' ability to address common maritime security challenges.

"The AFP remains committed to defend the nation's sovereignty and sovereign rights while advancing defense cooperation with regional and international partners in support of national and regional security," he said.