Sources : U.S. destroyer has entered Somali territorial waters to pursue ship . Pirates hijack ship and cargo off Somalia ; benzene is highly flammable . U.S. warship attacked with permission of Somali government .
Sources : U.S. destroyer has entered Somali territorial waters to pursue ship . Pirates hijack ship carrying benzene off Somalia ; benzene is highly flammable . U.S. destroyer working with permission of Somalia government .