A disagreement between China and the Philippines over the ­presence of more than 200 Chinese vessels at a disputed South China Sea reef has sparked concerns Beijing is upping efforts to control the contested waters. Philippine Defence Secretary Delfin Lorenzana has demanded the boats leave Whitsun Reef, which is in a shallow coral region in the Spratly Islands, about 320km west of Palawan in the Philippines. Manila has threatened to deploy additional navy ships to counter what it called an “incursion” and “militarising the area” by vessels that Lorenzana classed as “maritime militia”. Beijing insists they are fishing boats sheltering from rough seas. Dr. Collin Koh, a Research Fellow from the RSIS in Singapore, suspected the vessels were not only fishing boats, and that they represented a challenge to Manila. “It’s by now an open secret that the Chinese authorities are in the midst of enhancing their maritime militia, especially its ability to fish and fight,” Koh said. “The fishers are expected, even when engaged in fishery production work, to perform their patriotic duty as maritime militiamen.