A growing number of American and Philippine officials are expressing worry over Chinese naval activity surrounding the Scarborough Shoal, a small island chain of reefs and rocks with a 29-mile perimeter in the South China Sea, 168 miles from the Philippine coast. Details of a Chinese militarization plan for the shoal were obtained by United States intelligence agencies over the last several months, according to defense officials.

Access to the shoal has been restricted by the People’s Republic of China since the Scarborough Shoal standoff in 2012. Both China and the Philippines claim the shoal, maintaining that they have had regular fishing activities in the area.

China denies that its island-building activities in the South China Sea are militarizing the area, but the surrounding countries are worried.

According to Washington Free Beacon, China’s plans for the Scarborough Shoal were confirmed when a “website for Chinese military enthusiasts posted a detailed plan … including a runway, power systems, residences, and harbor capable of supporting Chinese Navy warships.”

Defense officials were not sure if the posts were of the actual plan of development or an earlier, conceptual stage, but Chinese authorities have used such websites to reveal new military developments in the past.

The U.S. military’s top commander in the Pacific, Adm. Harry Harris, has proposed a more muscular response to China’s island building, but he has met with strong resistance from the White House.

Adm. John Richardson, head of U.S. naval operations, also has concerns about Chinese activity around the shoal. Richardson worries that an international court ruling, expected in early June, on a case brought by the Philippines against China over its South China Sea claims could trigger Beijing to declare an exclusion zone in the busy trade route.

Philippine diplomat Jose Cuisia Jr. told a news conference in Manila on April 12 that any Chinese move to turn a disputed shoal into an island would be a “very provocative” step.

With $5.3 trillion of trade passing through what China asserts as its sovereign territory every year, it is no small dispute. To understand what China has already claimed, read “Literally and Littorally, China Is Gaining Ground.”