Iraqi troops and Shiite militias have reportedly been engaged in fierce clashes with the Islamic State in an effort to retake the city of Tikrit north of Baghdad.
However, reports are suggesting the advance has been slowed by roadside bombs and suicide attacks.
Iraqi Lieutenant-General Abdul-Amir al-Zaidi.
"Our troops launched a wide-scale battle at 7:15 against their targets. They were able to pound the hideouts of Islamic State militants with rockets and artillery. Our attacking force was backed by jet fighters. God willing, we will defeat IS militants from this district and other areas. And we will continue chasing them."
The military operations, which began on Sunday, also include militia fighters from local tribes.
Iranian commanders are also helping to co-ordinate the operation, which is not being backed by US-led coalition air strikes.
Tikrit lies along the Tigris River, just 130 kilometers north of Baghdad.
Taking the city will be key if Iraqi troops hope to move on to Mosul, which is Iraq's second largest city, as well as the gateway to the north of the country, much of which is under the control of Islamic State fighters.
