UN's grim week: 6 peacekeepers and an interpreter killed, while more staffers detained in Yemen

It's been a grim week at the end of a tough year for the United Nations: Six U.N. peacekeepers were killed in a drone attack in Sudan. A U.N. interpreter died while in the custody of South Sudan's security personnel. And 10 more U.N. staff were detained by Yemen's Houthi rebels.