Jakarta. The Philippines lodged a diplomatic protest Thursday against China’s plan to establish a nature reserve at Scarborough Shoal, one of the most hotly contested territories in the South China Sea, and demanded that Beijing immediately withdraw the move.

China’s State Council on Wednesday announced the approval of a national nature reserve at the shoal, also known as Bajo de Masinloc in the Philippines. The notice said details about the project’s area and scope would be released separately by the National Forestry and Grassland Administration.

The shoal is among many islands, reefs, and islets in the South China Sea claimed by China and its neighbors, including the Philippines, Vietnam, Malaysia, Brunei, and Taiwan.

The Philippine Department of Foreign Affairs said the protest was filed “against this illegitimate and unlawful action by China as it clearly infringes upon the rights and interests of the Philippines in accordance with international law.”

“The Philippines urges China to respect the sovereignty and jurisdiction of the Philippines over Bajo de Masinloc, refrain from enforcing and immediately withdraw its State Council issuance, and comply with its obligations under international law,” the department said in a statement.

Manila has declared that any Chinese construction activity at Scarborough would cross a red line.

China’s State Council said the creation of the “Huangyan Island National Nature Reserve” was intended to preserve the shoal’s biodiversity and ecological sustainability.

But Philippine Ambassador to Washington Jose Romualdez, a vocal critic of Beijing’s actions, said the plan was clearly political. “It’s obviously another maneuvering move by China to justify their 10-dash line claim,” he said, referring to Beijing’s expansive claims over nearly the entire South China Sea.

Scarborough Shoal has been the site of frequent maritime confrontations between Chinese and Philippine vessels. Just last month, a Chinese navy ship accidentally collided with a Chinese coast guard vessel while attempting to block a Philippine patrol near the shoal.

The United States, which has no territorial claims in the South China Sea, has repeatedly warned that it is obligated under its mutual defense treaty to defend the Philippines if its forces, ships, or aircraft come under armed attack, including in the disputed waters.