Crude oil prices on Friday surged to a fresh high of $84 a barrel on concerns that Turkey might soon launch an invasion of northern Iraq in an attempt to hit Kurdish militants it accuses of attacking Turkish targets.

Such an attack could destabilise the Kurdistan region, the only relatively peaceful area in Iraq. But public outrage against the separatist Kurdish PKK is running high after recent attacks and Turkey’s parliament is set to vote next week on a government request for authorisation of a military operation.