Suicide bombings killed at least 18 people and wounded more than 30 in two cities north of Baghdad on Sunday, officials said.
One bomber detonated an explosives-rigged vehicle at the southern entrance to Tikrit, while the other blew up an ambulance in Samarra, the officials said.
There was no immediate claim of responsibility for the attacks, but the Islamic State group frequently carries out suicide bombings in Iraq.
Iraqi forces are fighting to retake Mosul from IS, the jihadist group's last major urban stronghold in the country.
IS has launched a series of diversionary attacks since the start of the Mosul operation on October 17 in a bid to draw both attention and forces away from the battle.
The Sunni extremist group overran large areas north and west of Baghdad in 2014, but Iraqi forces backed by US-led air support have since regained significant ground.