North Korea has been accused of spying on South Korea after a suspected Pyongyang drone was spotted on the site of a U.S. missile interceptor system, Seoul's military officials said Tuesday. The Terminal High Altitude Area Defense (THAAD) anti-missile system, which is designed to intercept and destroy ballistic missiles, is being deployed in Seongju in order to protect South Korea from Pyongyang's growing threats. According to Yonhap News, the small unmanned aerial vehicle equipped with a Sony-made camera was found last week on a mountain near the inter-Korean border. The drone had apparently crashed close to the THAAD site. The South's military took the drone in custody and analysed the content of the 64-gigabyte memory chip.