Questions are being raised about Spain's rail safety as authorities launch an official investigation into the cause of Wednesday's high-speed train collision, which killed at least 68 people and wounded around 100 more, in the country's second fatal rail crash this year. 

At least 68 people were killed Wednesday after two high-speed trains collided in Spain's central Toledo province, regional authorities confirmed, with high-speed rail services between Madrid and Andalusia suspended. It is Spain's second deadly train crash in less than a year. Prime Minister Pedro Sanchez said the country would observe three days of mourning.