The device exploded as a vehicle carrying three fighters of Al-Hashd Al-Ashaeri was passing in the Dibis district, 45 kilometers west of Kirkuk city, Police Captain Hamed al-Obeidi, told Anadolu Agency. 

The officer suggested that the roadside bomb was planted by the ISIL terrorist group. 

Al-Hashd Al-Ashaeri is a group of Sunni tribal fighters which operates under the umbrella of the Shia-predominant Al-Hashd Al-Shaabi fighting force. 

Last December, officials in Baghdad declared that the ISIL terrorist group's military presence in Iraq had been all but dismantled after a three-year war. 

However, from time to time, Iraqi officials announce operations against ISIL-affiliated "sleeper cells" in certain parts of the country.