A former archbishop of Mosul has warned that the totalitarian ideology of the Islamic State (IS) group may continue despite the recent recapture of the city and its surrounding areas by Iraqi forces.

Chaldean Archbishop Amel Nona was among the thousands of Iraqi Christians who fled their homes in northern Iraq in summer 2014 when IS jihadists threatened to kill any who did not leave or convert to Islam. He has since moved to Australia, where he ministers to Chaldean Catholics who have resettled there.

Speaking to the Catholic charity Aid to the Church in Need, Archbishop Nona said: “It is not easy to say that ISIS is defeated in Mosul and beyond.

Archbishop Nona succeeded a man who was murdered by insurgents, then his congregation was threatened with slaughter by IS

“ISIS is a of way of thinking and acting and this results in a society thinking that it has the right to do what it wants, that their belief is the only one, and that this should be enforced on all other people.

“So although the city of Mosul has been liberated militarily, there is still another battle ahead: to change and defeat the cradle of this kind of thinking and acting.

According to the archbishop, Christians were scared to return to their homes in Mosul because levels of support for IS’s ideology in Mosul remained high.

“Christians affected by the occupation of ISIS are not able to easily live a normal life there when they know that the society responsible for making ISIS still exists – as it was three years ago,” he said.

The archbishop said when he first heard that Mosul had been liberated, he “couldn’t stop thinking” about the displaced Christians, and the fate of “our very ancient churches and our Christian heritage” after three years of occupation.

Asked if he thought the Christian community would return to Mosul, he said it was still too early to know.

When IS invaded Mosul in June 2014 the archbishop helped orphans in the Church’s care, and single mothers and their children, to escape. They fled to Christian-majority villages in the Nineveh Plains but had to flee again two months later when Kurdish Peshmerga troops retreated with only 30 minutes’ warning. The Christians, then undefended against the advancing IS militants, fled north into the Kurdish region, from where some have since resettled outside the Middle East.

Nona’s predecessor in Mosul, Paulos Faraj Rahho, was kidnapped and murdered by members of Al-Qaeda in Iraq, the forerunner to IS, in 2008.

The archbishop’s motto is: “During times of crisis and persecution, we must remain full of hope”.