SNIPPET: "South Korea's naval unit operating off the coast of Somalia has been placed on high alert over Somali pirates' possible attacks using U.S. surface-to-air guided missiles against its helicopter, according to intelligence and Navy sources Monday. The National Intelligence Service and the Defense Security Command recently provided the classified information to the Cheonghae Unit that Somali pirates seemed to have acquired ``Stinger'' missiles from al-Qaeda, said the sources." SNIPPET: "The unit reported the potential threat missiles to the Navy command here and requested data on the weapon, the source said. A military spokesman in Seoul said there was no...