MANILA, March 4 (Reuters) - The Philippines said on Saturday it had spotted a Chinese navy ship and dozens of militia vessels around a contested Philippine-occupied island in the South China Sea, as territorial tensions mount in the area. Thitu in the Spratly island chain is Manila's biggest and most strategically important outpost in the South China Sea, a body of water largely claimed by Beijing where several countries have conflicting territorial claims. See here for a complete list of exchanges and delays