Iraqi pro-government forces, including fighters from the Shiite Muslim Al-Abbas popular mobiliaation unit, take part in an operation to retake the Baiji oil refinery from ISIS jihadis, on April 15, 2015. The refinery -- some 200 kilometres (120 miles) north of Baghdad -- once produced some 300,000 barrels of refined products per day, meeting half the country's needs. AFP PHOTO / MOHAMMED SAWAF