MANILA, June 10 -- The object that has two governments exchanging diplomatic papers measures six meters by six, carries what looks like an antenna, and appeared to have people aboard. In most of the world it would be a curiosity. At Scarborough Shoal, where the South China Sea's longest staring contest is conducted, a manned raft is a potential foundation stone, and the Philippines has decided to treat it as one.

Manila's foreign ministry said it had undertaken appropriate diplomatic action against China over the structure's illegal presence at the shoal, NBC News reported. The Philippine task force monitoring the area said the platform was first spotted at the entrance to the shoal's lagoon and later inside it, and satellite images obta...