China said it had carried out a scientific expedition in Scarborough Shoal, amid renewed confrontation with the Philippines over the disputed South China Sea atoll.

The research mission – which began on May 20 – involved deploying a floating platform for environmental monitoring and sampling, the Chinese Academy of Sciences’ South China Sea Institute of Oceanology said in a statement on Wednesday.

It came after Manila lodged a formal diplomatic protest on Tuesday against what it called the “illegal presence” of a floating structure in Scarborough Shoal.

The National Task Force for the West Philippine Sea – an inter-agency body that oversees Manila’s maritime strategy in the South China Sea – said aerial monitoring of the shoal had detected a floating platform that appeared to be an antenna.

China’s foreign ministry said it was legitimately exercising its right to carry out activities “including scientific research” at Scarborough Shoal and urged the Philippines to stop its “sensationalist hype”.

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The research institute said its expedition had covered the entire shoal with the aim of collecting data on the geological evolution and physiological responses of coral reefs to environmental changes.