A university student acting as North Korean leader Kim Jong-il holds a mock North Korean torpedo during a performance about the sunken South Korean naval ship accident during an anti-North Korea rally in Seoul May 30, 2010. Relations on the peninsula have plunged back into the Cold War freezer following the March sinking of the South Korean warship, killing 46 sailors, which an international investigation last week said was caused by a North Korean torpedo in one of the deadliest incidents since the end of the 1950-53 Korean War. REUTERS/Jo Yong-Hak (SOUTH KOREA - Tags: MILITARY POLITICS CIVIL UNREST IMAGES OF THE DAY)