China has militarized three islands it built in the disputed South China Sea, says Admiral John Aquilino, commander of U.S. Indo-Pacific Command. “I think over the past 20 years, we’ve witnessed the largest military buildup since World War II by the PRC (People’s Republic of China),” Aquilino told The Associated Press. “They have advanced all their capabilities and that buildup of weaponization is destabilizing to the region.” China has equipped Mischief Reef, Subi Reef, and Fiery Cross Reef with anti-ship and anti-aircraft missile systems, laser and jamming equipment and aircraft hangers, Aquilino said. The missile systems could easily target any civilian and military planes flying over the disputed waters, he added. “So that’s the threat that exists, that’s why it’s so concerning for the militarization of these islands,” Aquilino said. “They threaten all nations who operate in the vicinity and all the international sea and airspace.” The U.S. Commander spoke to AP onboard a U.S. navy reconnaissance aircraft that flew near Chinese-held outposts in the South China Sea’s Spratly archipelago. During the patrol, the plane was warned by Chinese callers that it had illegally entered ‘China’s territory’ and told to move away. The pilot of the aircraft responded saying he was conducting “lawful military activities beyond the national airspace of any coastal state”.