South Korea confirmed North Korea designated a no-fly zone on the eastern coast of the peninsula on Nov. 11 as concern grows that Pyongyang could be preparing to test-fire a missile, UPI reported. North Korea had designated an extensive area near the port city of Wonsan as a no-navigation zone from Nov. 11 to Dec. 7, South Korean news network MBN reported on Monday. A military source said South Korea is on standby for new developments, and that it's possible Pyongyang could test-launch a short-range rocket or a scud ballistic missile. The speculation comes at a time when North Korea activities have receded at Sohae Satellite Launching Station in Tongchang-ri, North Pyongan province, where North Korea built a new 220-foot platform, as well as fuel and storage facilities for oxidizer. Sohae is the long-range missile platform where in 2012 North Korea launched the expandable carrier rocket Unha-3, which fell into the Yellow Sea. The debris of a second-stage launch fell into the Philippine Sea after an object had entered orbit. In May, North Korea released new footage of what it claims is the triumphant lift-off of a submarine-launched ballistic missile, and North Korean submarines were active between May and September, according to satellite imagery.