Prime Minister Haider al-Abadi said on Sunday Baghdad would take the "necessary measures" to protect Iraqi unity, speaking on the eve of an independence referendum in the Kurdish autonomous region.

"To take a unilateral decision affecting the unity of Iraq and its security, and the security of the region, with a referendum on separation is unconstitutional and against civil peace. We will take the necessary measures to preserve the unity of the country," Abadi said in a televised address.