The blast occured amid Iraqi parliamentary elections on the day.
Two of the dead are voters while the third is an observer for the elections in the town of al-Khan, security sources in Kirkuk said.
The governor of Kirkuk, Rakan Said al-Jubouri, said earlier that the situation in the city center did not witness any security breaches, except for some violations in areas south of Kirkuk and its west which did not affect the conduct of the electoral process, NRT reported.
The parliamentary election was the first general election since Iraq’s victory over Islamic State in December last year.
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