BAGHDAD (AP) — Iraqi Vice President Ayad Allawi warned on Monday there could be a "civil war" over the Kurdish-administered city of Kirkuk if talks over Kurdish independence are left unresolved.

Allawi, in an interview with The Associated Press, urged Kurdish leader Masoud Barzani, as well as Iraq's central government and its Iranian-backed militia forces, to show restraint and resolve their disputes over the oil-rich city.

The head of the Asaib al-Haq militia Qais Khazali warned worshippers in a sermon Sunday that Iraq's Kurds were planning to claim much of north Iraq, including Kirkuk, for an independent state, after Iraq's Kurds voted for independence in a controversial but non-binding referendum two weeks ago.

He said it would be tantamount to a "foreign occupation," according to remarks reported by the Afaq TV channel, which is close to the state-sanctioned militia.

Allawi, a former prime minister, said any move by the country's Popular Mobilization Front militias, which include the Asaib al-Haq, to enter Kirkuk would "damage all possibilities for unifying Iraq" and open the door to "violent conflict."

"The government claims they control the Popular Mobilization Forces. If they do they should restrain them, rather than go into a kind of civil war. And there should be a restraint on Masoud Barzani and the Peshmerga not to take aggressive measures to control these lands," said Allawi.

Kirkuk was included in the September referendum even though it falls outside the autonomous Kurdish region in the country's northeast. The ethnically-mixed city has been administered by Kurdish forces since 2014, when government forces fled from the advancing Islamic State group.

Barzani held the referendum over the strong objections of Baghdad, Ankara, and Tehran, enraging leaders in the regional capitals.

Prime Minister Haidar al-Abadi demanded the Kurdish self-government annul the results and called for joint administration over Kirkuk. Baghdad closed the airspace over the Kurdish region to international flights.

Turkey and Iran also threatened punitive measures against the Kurdish region, fearing Kurds in their own countries would renew their campaigns for self-rule.

"Iraqis should be left alone to discuss their own problems without interference," said Allawi. "Kirkuk has become a flashpoint."

Barzani has not declared independence for any part of northern Iraq.