Tensions are running high surrounding the Korean peninsula as North Korea has threatened the safety of civil aircraft in its airspace over the Sea of Japan. In a statement North Korea warned, "Security cannot be guaranteed for South Korean civil airplanes." Fueling the tension is the upcoming joint South Korean-U.S. military exercise, which North Korea views as a preparation for attack. The United States and South Korea maintain the exercise is routine and meant to review defensive procedures. This time, however, nerves are on a tighter string since North Korea is rumored to be planning a test launch of a long-range missile. Singapore Airlines, for its part, has announced it is avoiding North Korean airspace until tensions ease.