Six security officials were killed on Saturday in an attack near the northern city of Kirkuk, local media reports said, as polling stations opened for the country's first elections since the rise of ISIS.
Security threats remain a key concern in Iraq's northern and Sunni areas where ISIS continues to carry out attacks on civilians and members of the security forces.
"The armed gunmen attacked checkpoints of the federal police near the village of Saadouniyah, 35 kilometers southwest of Kirkuk, killing four members of the federal police, two of Hashed Al Shaabi and wounding two others," Al Arabiya reported.
No affiliation was given to the gunmen but ISIS had threatened to attack polling stations before the vote.
The oil-rich city of Kirkuk is one of Iraq’s most diverse cities, home to Iraqi Arabs, Turkmen, Christians and Kurds.
In an audio message last month, an ISIS spokesman said anyone who participates in the vote would be considered an infidel, or a disbeliever.
"We warn you, Sunnis of Iraq, of these people [Shiites] taking power. Polling stations are a target for us, so stay away from them," Abu Al Hassan Al Muhajer said.
Saturday’s polls are the first to be held since Iraqi Prime Minister Haider Al Abadi declared victory over the terror group last December. The elections are also the fourth parliamentary elections since the fall of former dictator Saddam Hussien in 2003.
Although the premier had declared victory against the terror group, he admitted last month that the country is still engaged in a fight against ISIS sleeper cells.
Mr Al Abadi said that he would “take necessary measurements” against the insurgents “if they threaten the security of Iraq”.
He pledged to send more forces to Kirkuk to “continue clearing operations”.
Meanwhile, clashes have been reported in the Shiite city of Najaf between supporters of the Saairun coalition, led by Shiite cleric Moqtada Al Sadr, and Prime Minister Haider Al Abadi's Victory Alliance.