In early 1995, the Philippines discovered a primitive Chinese military structure on Mischief Reef in the Spratly Islands, one hundred and thirty nautical miles off the coast of Palawan. The Philippine government issued a formal protest over China's occupation of the reef and the Philippine Navy arrested sixty-two Chinese fishermen at Half Moon Shoal, eighty kilometers from Palawan. A week later, following confirmation from surveillance pictures that the structures were of military design, President Fidel Ramos had the military forces in the region strengthened. He ordered the Philippine Air Force to dispatch five F-5 fighters backed by four jet trainers and two helicopters, while the navy sent two additional ships. The People's Republic of China had claimed that the structures were shelters for fishermen but these small incidents could have triggered a war in the South China Sea.