Advances by the group calling itself the Islamic State in recent weeks have driven hundreds of thousands of people from their homes, including Sunni and Shia Muslims.
Many Shia ethnic Turkmen say they had to flee their homes due to persecution at the hands of Sunni rebels.
The development came as Sunnis accuse Iraqi security forces, who follow orders from the Shia-led government of Nouri al-Maliki, of extrajudicial executions.
Many fear that the conflict will further divide the country along sectarian lines and destroy any harmony that existed among religious groups.
Al Jazeera's Zeina Khodr reports from the Iraqi province of Erbil.