The Islamic State launched a counter-attack on the city of Kirkuk, killing dozens of people including security officers and workers at a powers station, Friday.
The attack is in response to Iraqi-led forces beginning their operation to take back Mosul, the last major ISIL stronghold in Iraq.
Kirkuk lies in an oil-producing region. Reuters reports, crude oil production facilities were not targeted. According to Reuters, Iraqi forces captured eight villages south and southeast of Mosul with air and ground support from the U.S.
Millions of residents are still believed to be in Mosul. The United Nations says the retake of Mosul will likely be the largest humanitarian crisis in recent memory, with millions of people being displaced.