NEW : Military says mission prompted by fear pirates could take hostages ashore . The U.S. military has said the raid was in response to a threat from Somali pirates. Owner Florent Lemacon , who was held hostage , dies in rescue ; four freed . French military attack pirates holding yacht from different directions . Two pirates also killed in rescue operation .
NEW : Military says mission prompted by fear pirates could take hostages ashore . NEW : Owner Florent Lemacon , who was held hostage , dies in rescue ; four freed . French military attack pirates holding yacht from different directions . Two pirates also killed in rescue operation .