Another 11 people were killed in less than 24 hours by shelling in Fallujah, held by anti-government fighters for over four months, a doctor said on Sunday.
The shelling, which hit various areas in the city’s south, also wounded four people, Doctor Ahmed Shami said.
The bloodshed late Saturday comes during vote counting from the April 30 general election, the first since US troops withdrew in late 2011, and amid a protracted surge in nationwide unrest.
In the deadliest attack, a bombing and shooting targeting the bus of Shia pilgrims killed 11 people and wounded 21, police and a doctor said.
The pilgrims were returning from Samarra north of the capital, when a roadside bomb blast on the outskirts of the town of Balad was followed by gunmen opening fire on the bus.
The worshippers had been holding commemoration rituals to mark the death of Imam Ali al-Hadi, the 10th of 12 imams who are key to the Shia faith.
His body lies in a venerated shrine in Samarra that also houses his son Hassan al-Askari, the 11th imam. Funerals for the victims were held on Sunday in southern Maysan province, an AFP journalist said.
Also on Saturday evening, police found the bodies of eight family members shot dead inside their home southeast of Baghdad.
It was unclear why the family had been targeted or who killed them.
The bloodshed comes just days after a parliamentary election, with incumbent Prime Minister Nouri al-Maliki seeking a third term despite the dramatic deterioration in security and widespread political opposition.
More than 3,000 people have been killed already this year, according to an AFP tally based on security and medical reports.
The unrest is the worst since Iraq emerged from a brutal internal war that killed tens of thousands of people in 2006 and 2007.