Gunmen from the Islamic State jihadist group on Friday publicly executed two young men for allegedly cooperating with Iraqi security forces, officials and witnesses said.
The killings were carried out in the middle of the crowded main market in the Zab area of Kirkuk province.
The IS jihadist group spearheaded a sweeping militant offensive in June that overran large parts of the country, including territory in Kirkuk.
Iraqi security forces and pro-government fighters are battling to regain ground with backing from a US-led air campaign and have retaken some areas, but three key cities are still in the hands of the militants.
IS, which also controls swathes of neighbouring Syria, has committed widespread atrocities in both countries, including hundreds of executions.