A U.S. Army M1A2 tank crosses Nam Han river on a South Korean military barge during a joint military exercise between the U.S. and South Korea in Yeoncheon near the border with North Korea, in South Korea, Thursday, May 30, 2013. According to U.S. military authorities, the training is aimed at enhancing the two allies' combined combat capabilities. (AP Photo/Ahn Young-joon) ( South Korea US Military Exercise )