The South Korean Navy fired warning shots Saturday night after two North Korean patrol boats crossed into South Korean waters, state media said. The two North Korean patrol boats separately crossed a maritime border in the Yellow Sea. One retreated after receiving a warning communication from the South Korean Navy, and the other retreated after two rounds of warning shots were fired, Seoul's Joint Chiefs of Staff told the state-run Yonhap news agency. Tensions between the two nations have run high since the mysterious sinking of a South Korean warship in the border area on March 26. Fifty-eight men escaped...