IRAQ’S northern city of Kirkuk was under curfew yesterday after overnight violence ahead of a deeply controversial independence referendum in Iraqi Kurdistan.

Shortly after sunset on Monday, gunmen on motorcycles opened fire on one of the offices of the Iraqi Turkmen Front, Mohammed Samaan Kanaan, in charge of the movement’s offices, told reporters. The guards returned fire, killing one and wounding two of the assailants, Mr Kanaan added.

Hours later, a police patrol that included the brother of the slain assailant attacked another office, triggering clashes, Mr Kanaan said. The fighting ended when a large police force reached the scene. No casualties were reported from the second bout of clashes.

Provincial police chief Brigadier General Khattab Omar said an investigation committee made was probing the incident.

He blamed “reckless, enthusiastic youths” for the skirmishes and said that arrests had been made, insisting the situation was under control inside the city.

The Kurdistan regional government (KRG) called the vote for September 25 in the three provinces it governs as well as other areas it claims, including oil-rich and multi-ethnic Kirkuk.

Both the Supreme Court and Iraq’s parliament have called for the referendum not to go ahead.

Opponents to the referendum have decried it as an attempt by KRG president Masoud Barzani of the conservative Kurdistan Democratic Party to strengthen his grip on power.

Meanwhile neighbouring Turkey, which has frequently attacked Kurdistan Workers Party guerillas inside northern Iraq, has threatened to “respond” to a Yes vote in the referendum.

Turkish troops are currently conducting military exercises just over the border.