Iraqi lawmakers sacked on Thursday the governor of Kirkuk over a referendum on Kurdish independence set for September 25 as Turkey warned the vote would “have a cost.”

The sacking of Najmaldin Karim came upon a request made by Prime Minister Haider Abadi after Kirkuk – an oil-rich province claimed by both the central government in Baghdad and the autonomous Kurdish region in northern Iraq – decided to take part in the referendum.

Iraq’s parliament on Tuesday voted down the plan in a session which prompted a walkout by Kurdish lawmakers.

The Turkish foreign ministry warned in a statement that the Iraqi Kurdish leaders’ call for the referendum was “worrying.”

The Iraqi Kurdish government’s “insistence on the referendum despite all friendly advice will definitely have a cost”, the ministry said, urging Erbil to return from their “erroneous approach.”

The ministry said it welcomed the decision made by the Iraqi parliament, adding that their vote was a “clear indicator of importance attached to Iraq’s political unity and territorial integrity.”

Kurdish leader Massoud Barzani has vowed to press ahead with the vote, calling it “a natural right”.

“Barzani’s referendum decision is a historic mistake. Turkey will follow policies that take Iraq’s territorial integrity as a basis,” Deputy Prime Minister Bekir Bozdag said.

“The northern Iraq referendum must be canceled, if not it will have a cost and retribution,” he said, adding the move would erode the region’s peace and bring security risks.