UN Secretary General Ban Ki-moon on Friday condemned the “brutal killings of civilians” by Islamic State jihadists in northern Iraq, saying the Sunni radical group was tearing apart whole communities.

The jihadists have taken control of large swathes of Iraq and Syria, and have declared a “caliphate” in the territory they control straddling the two countries.

The UN human rights chief earlier this week accused the group of “ethnic and religious cleansing” in Iraq, saying their reign of terror against non-Arab ethnic groups and non-Sunni Muslims involved targeted killings, forced conversions and abductions.

Ban added his voice to the growing concerns, telling a United Nations conference on the Indonesian resort island of Bali: “All major faiths value peace and tolerance.”

Illustrative photo of Islamic State fighters marching in Syria (photo credit: YouTube)

Illustrative photo of Islamic State fighters marching in Syria. (photo credit: YouTube)

“That is why I am especially outraged by the reports from Iraq of brutal killings of civilians by ISIL,” he added, using the old name for the Islamic State (IS).

“Whole communities that had lived for generations in northern Iraq are being forced to flee or face death just for their religious beliefs.”

Ban said that communities should not be threatened simply because of “who they are and what they believe.”

In her comments earlier this week, UN rights chief Navi Pillay said that persecution of minority groups in Iraq by IS amounted to crimes against humanity.

She said that minority groups targeted include Christians, Yazidi, Shabaks, Turkomen, Kakae and Sabaeans.

After occupying parts of Syria, the jihadists took over swathes of Iraq with a lightning offensive in June, sparking widespread international alarm.

IS has also been accused of atrocities in Syria, with a UN probe this week charging that public executions, amputations, lashings and mock crucifixions were a regular fixture in jihadist-controlled parts of the country.

The group also claimed the killing of US journalist James Foley, who was kidnapped in northern Syria in 2012, last week releasing a video that showed a masked militant beheading him.