Pyongyang has threatened immediate strikes against South Korea's navy if its ships enter the North's waters. Tensions between the neighbours have risen after an international investigation concluded that a northern torpedo sank a Southern warship in March. Pyongyang denies its blame. Moscow's sending a team of specialists to confirm the findings. Ivan Eland, the director of the Center on peace and liberty at the Independent Institute in the U.S. says South Korea is perfectly capable of defending itself, and the United States presence in the region is only adding to the tension