The South Korean military shot down an unidentified balloon over the Yellow Sea in March as it crossed the western maritime border, sources said Friday. The Marine Corps stationed in Baengnyeong Island near the Northern Limit Line (NLL), a de facto inter-Korean maritime border, detected the unidentified flying object measuring up to 2 meters and drifting without a power device, according to the sources familiar with the issue. A KA-1 light attack aircraft was deployed near the front-line island and shot it down as it kept crossing the NLL. The military attempted to retrieve the object at sea but failed to salvage it, they noted. Military officials speculate that the object may have flown from North Korea, though they do not rule out the possibility of it originating from China. Spy balloons from China have been spotted in the United States and Taiwan in recent years. Source: Yonhap News Agency