Stock shots of Gao in northern Mali Two Dutch United Nations peacekeepers were killed on Tuesday when their Apache attack helicopter crashed in northern Mali, the Dutch military said, calling it an accident. The helicopter, from the UN's MINUSMA mission, crashed about 20 kilometres (12 miles) from Gao, a source from the city's airport told AFP, adding that two people were injured and subsequently died. STOCK SHOTS of Gao in northern Mali