South Korean Marines fired rifles at a South Korean commercial aircraft flying near the sea border with North Korea, thinking it was one of the communist North's jet fighters, but they never hit their target, military sources said on Saturday. The shooting illustrates the level of tension between the two Koreas, still technically at war after the 1950-53 Korean conflict ended in a truce rather than a peace treaty, which came close to all-out war last year. A Marine Corps spokesman said two soldiers guarding an island on the waters off the South's western city of Incheon fired their K-2...