The Islamic State of Iraq and the Levant (ISIL) group has claimed responsibility for attacks that have killed at least 57 people near the eastern Iraqi city of Baquba.
More than 80 people were injured in Monday's attacks, which happened in predominantly Shia areas in Diyala province.
The deadliest attack occurred in the town of Huwaydir, 4km north of Baquba. Police said a suicide car blast tore through a marketplace, killing dozens of people.
"A suicide bomber driving a booby-trapped vehicle blew himself up in the middle of the central market area in Huwaydir," a police lieutenant-colonel was quoted by AFP news agency as saying.
Another suicide bomber drove his explosives-laden vehicle past a checkpoint before blowing himself up in Kanaan district, killing at least 10 people and wounding the same number, a police captain said.
ISIL, which controls large expanses of the country's north and west, said in a statement circulated online by supporters that the targets were "rejectionists", as the Sunni group refers to Shia Muslims.
Al Jazeera's Mohammed Jamjoom, reporting from Baghdad, noted that the bombings were the second deadliest ones in the province since late July, when at least 100 civilians were killed in attacks also claimed by ISIL.
Residents of Diyala have been calling for greater protection after the attacks last month.
The government in Baghdad pledged to apprehend the culprits and better secure the province, where a number of towns were captured by ISIL last year.
Iraqi forces and Kurdish fighters since have retaken those areas, but clashes between ISIL fighters and security forces continue.
ISIL currently controls about a third of Iraq and Syria.
Earlier, Iraq's cabinet approved a proposal by Haider al-Abbadi, the prime minister, to overhaul the government bureaucracy, scrapping three vice presidential posts and the offices of three deputy prime ministers.
The cabinet's move, which came on Sunday, will still need parliamentary approval.
The six posts under threat represented various political and sectarian blocs in the government.
The plan also effectively would push out of government Minister Nouri al-Maliki, Abbadi's predecessor, widely criticised for inflaming sectarian tensions and appointing loyal, less-qualified senior officers to Iraq's military before ISIL's advance last year.
However, Maliki issued a short statement backing the proposed plan.
Source: Al Jazeera and agencies