Islamic State extremists have set fire to a number of oil wells in Iraq, according to media reports.
The fires are said to have taken hold in three wells west of the city of Kirkuk, which is still under the control of militants.
The move is an attempt to slow US backed forces who are attempting to retake control of the area from the caliphate.
Burning oil wells creates a thick black smoke which hampers airstrikes and other military aerial action.