Iraq's Popular Mobilization Forces (PMF) mounted an operation against militants suspected of masterminding a car bomb attack in Tikrit on Tuesday.
Foot soldiers backed up with helicopters and armoured personnel carriers were sent into the area west of the Tigris River. A number of wanted persons were identified and detained pending further investigation.
Five people were killed and 16 others wounded in a car bomb explosion in Tikrit on Sunday.
Militants from the self-proclaimed Islamic State (IS; formerly ISIS/ISIL) reportedly maintain a strong presence in the area. The group has switched to insurgent tactics since it was defeated in Iraq's urban areas last year. It has claimed responsibility for a number of bombings in recent months.