Iraqi forces launched an operation on Tuesday to retake a northern town from ISIL, a stepping stone in the campaign to recapture the main city of Mosul before year end. Tens of thousands of civilians are thought to be trapped in Sherqat, which lies on the Tigris River 100km south of Iraq's second-largest city. It has been surrounded by Iraqi troops and militias allied to the government. Officials have warned for months of a humanitarian disaster inside, where residents living under Islamic State of Iraq and the Levant's harsh rule say food supplies have dwindled and prices soared. "The operation to liberate Sherqat started at 5:30am [0230 GMT] from several directions ... with the support of coalition forces," Joint Operations Command spokesman Yahya Rasool told the AFP news agency.