Monday's shootings and bombings killed 32 people and injured 92 others, with some suicide bombers detonating their explosives at the polling centers.
Iraqi police and military forces were permitted to cast their votes over two days ahead of the April 30 election day.
On Friday, three bombs exploded in Baghdad during a Shia election rally for the Asa'ib Ahl al-Haq party, killing 31 people. The Islamic State in Iraq and Levant terrorist group claimed responsibility for that attack.
The United Nations conveyed Secretary General Ban Ki-moon's condemnation of electoral-focused violence and called on "all political leaders and personalities to create the conditions necessary to enable all Iraqi men and women to participate in the electoral process and have their say on the future of the country."