Koreas Exchange Shots Off Coast

North and South Korean naval patrol boats exchanged fire on Tuesday near the island of Daecheong-do, 20 miles off the North Korean coast. No South Koreans were killed in the skirmish, which began when a North Korean patrol boat entered disputed waters claimed by South Korea and ended when it retreated after being damaged by the South Korean boat, according to Korean news agency Yonhap. The sea beyond the "northern limit line," a border set by the U.N. but never acknowledged by North Korea, was the site of clashes between the two countries' navies in 1999 and 2002. President Obama is due to visit Seoul next week as part of a trip to Asia, where North Korea's nuclear ambitions are likely to be a major part of discussions.