A U.N. peacekeeping helicopter was shot down in eastern South Sudan by the country's military on Friday, killing all four crew members onboard, the U.N. peacekeeping operation in the country said. “The helicopter was not carrying any passengers," the U.N. Mission in South Sudan (UNMISS) said in a statement. “The mission extends its heartfelt condolences to the families of the crew." UNMISS has started an investigation to establish the circumstances around the crash of the MI-9 helicopter, which happened near the settlement of Likuangole, in the state of Jonglei, where it had been on a reconnaissance flight. Initial reports indicated that the helicopter crashed and burned. UNMISS immediately launched a search-and-rescue operation, which confirmed the death of all four crew members. In communications between UNMISS and the Sudan People's Liberation Army (SPLA), the mission was told that the SPLA had shot at a helicopter in the Likuangole area on Friday. UNMISS was created after South Sudan formally seceded from Sudan in mid-2011, six months after a referendum agreed to under a 2005 peace deal that ended decades of civil war that killed about 2 million people.