Twelve Turkish soldiers have died after being exposed to methane gas while searching a cave in northern Iraq, the Turkish Ministry of National Defence said. At least 19 personnel were exposed to the gas during the search and clear operation on Sunday, and immediately taken to hospital. By Monday, 12 had died, the ministry said. President Recep Tayyip Erdogan said he received the news with "great sorrow" and extended his condolences to the soldiers' families and to the Turkish Armed Forces. Methane gas is not directly toxic, but can be deadly as it can become suffocating, especially in tight, enclosed...