The Latest on the developments in Iraq where Iraqi forces and their allies launched a major offensive this week to retake Mosul, the country's second-largest city from the Islamic State group (all times local):

9:35 a.m.

The Islamic State group says its fighters have stormed a government compound in the northern Iraqi city of Kirkuk.

The claim was carried by the IS-run Aamaq news agency early on Friday, and could not immediately be verified.

Witnesses in Kirkuk say militants attacked two police compounds early Friday and reported hearing heavy gunfire and explosions.

Live footage from the Kurdish Rudaw TV shows smoke rising from the city. The station quoted however Kirkuk Governor Najmadin Karim as saying that militants have not seized any government buildings.

Kirkuk is around 170 kilometers (100 miles) from the IS-held city of Mosul. Iraq launched a massive operation to retake Mosul, the country's second largest city, earlier this week.

The witnesses spoke on condition of anonymity because of security concerns.

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8:15 a.m.

Witnesses in the Iraqi city of Kirkuk say armed militants have attacked a local police compound and that fighting is underway.

They say multiple explosions have rocked the city so far in Friday's assault and that gunfire could be heard ringing through the city.

There were no immediate reports of casualties.

The attack comes as the Iraqi government and Kurdish forces are making a major push to drive Islamic State militants from Iraq's second-largest city of Mosul. The witnesses spoke on condition of anonymity as they are concerned for their safety.

Kirkuk is an oil rich city some 290 kilometers (180 miles) north of Baghdad that is claimed by both Iraq's central government and the country's Kurdish region.