NATO said Monday that one of its soldiers had gone missing in restive southern Afghanistan, sparking a manhunt. \"An International Security Assistance Force service member has been listed as duty status whereabouts unknown in southern Afghanistan. There is an active search effort in progress,\" it said. Afghan police officials in the southern province of Helmand, where mostly American and British troops are fighting a Taliban insurgency, said a British soldier had been kidnapped in the Gereshk area of Nahri Sarraj district. A spokesman for the British embassy in Kabul, Will Calladine, gave no further details, but said: \"Obviously this is a sensitive issue. Our primary concern is for the person\'s safety.\"