"The secretary-general expresses his grave concern at the deepening crisis in Iraq and the rising number of civilian deaths and injuries, with over one million Iraqis having fled their homes due to the fighting," Xinhua quoted a statement issued here by Ban's spokesperson.
"The secretary-general calls on all parties to the conflict ensure that persecution of civilians based on their religion or ethnic background cease immediately."
The statement came as hundreds of thousands of Iraqis were driven from their homes with Islamic insurgents advancing across the Middle East country. Over a million Iraqis have been displaced this year, half within the last couple of weeks, the UN said.
Iraq has seen a deteriorating security situation since June 10
Iraq has seen a deteriorating security situation since June 10 when bloody clashes broke out between security forces and hundreds of Sunni militants who took control of Mosul, Iraq's second largest city.
The militants later seized swathes of territories after Iraqi security forces withdrew from their posts in Nineveh and other predominantly Sunni provinces.
At least 900 civilians have been killed since June 5, when Islamic State in Iraq and Levant (ISIL), an al Qaeda offshoot, Islamic State in Iraq and Greater Syria (ISIS) and its allies began their sweep across the country, and 650 have been wounded in fighting in Nineveh, Salah al-Din and Diyala, he said, citing updated figures.