Iraq's ethnically-mixed Kirkuk province, long claimed by both the Arab-led central government and the autonomous Kurdish region, voted Tuesday to take part in a vote on Kurdish independence slated for next month.

Iraq's Kurds plan to hold the controversial referendum on Sept. 25 in three governorates that make up their region as well as disputed areas that are controlled by Kurdish forces but claimed by Baghdad. Iraq's central government is opposed to the referendum.

In a statement released after Tuesday's session, the provincial council said the proposal won a "majority," without providing further details. Arab and Turkmen councilmen reportedly boycotted the meeting.

Oil-rich Kirkuk is home to a mix of Arabs, Kurds, Turkmen and Christians. Kurdish forces took control of the province and other disputed areas in the summer of 2014, when the Islamic State group swept across northern and central Iraq and the Iraqi armed forces crumbled.

Turkey and Iran are also opposed to the referendum, fearing it could inspire Kurdish separatists within their own borders. The U.N. mission to Iraq has said it will not be "engaged in any way or form" in the vote.

Turkey said the Kirkuk vote was "unacceptable," calling it "another link in the chain of mistakes" and a violation of the Iraqi constitution.

"Insisting on pursuing this dangerous course will not serve the interest of (the autonomous Kurdish region) or of Iraq, it will not be accepted by the international community, and will not contribute to regional peace and stability," The Turkish Foreign ministry said in a statement.

The vote has even faced criticism inside Iraq's Kurdish region, from those who say it should be postponed until new parliamentary and presidential elections have been held. Kurdish regional President Masoud Barzani's term expired in 2015.

Iraq's Kurdish region has enjoyed a high degree of autonomy since the U.S. imposed a no-fly zone over northern Iraq after the 1990 Gulf War. It has its own parliament and armed forces, flies its own flag, and has been a close U.S. ally against IS and other militant groups. But relations with Baghdad have grown strained in recent years over oil and the disputed areas.