Car bombings in Baghdad and the Iraqi province of Diyala have left at least 30 people dead.
The most destructive of the attacks was in the Iraqi capital's eastern district of al-Jadida, a predominantly Shi'ite area heavily targeted by car bombs in recent years.
At least 19 people were killed and 43 wounded in the blast near a market on Tuesday (local time), a police colonel and hospital sources said.
Another four people were killed and 10 wounded in a similar attack in the southern neighbourhood of Zafaraniya.
Islamic State claimed responsibility for both attacks, saying they had targeted Shi'ite militiamen, a claim it often makes even when most of the victims are civilians.
A car bomb also struck a joint police and army checkpoint in Tarmiya, a town which lies on of the main highways north of Baghdad, police said.
At least three members of the security forces were killed and nine wounded.
Also on Tuesday, a car bomb went off in Mandali, a town in the eastern province of Diyala near the border with Iran, killing at least four people.
A huge suicide car bomb claimed by IS killed dozens of people in Khan Bani Saad, a town just north of Baghdad, on Friday.