Taiwan is building a $100 million port next to an airstrip on the lone island it administers in the disputed South China Sea, a move that is drawing hardly any reaction from the most assertive player in the bitterly contested waters — China.

The reason, say military strategists, is that Itu Aba could one day be in China's hands should it ever take over Taiwan, which it regards as a renegade province.

While Itu Aba, also called Tai Ping, is small, no other disputed island has such sophisticated facilities. Its runway is the biggest of only two in the Spratly archipelago that straddles the South China Sea, and the island has its own fresh water source.