Pope Francis called on the international community on Thursday to protect the mostly Christian communities of northern Iraq fleeing a lightning advance by jihadist militants.

A statement delivered by his spokesman said the pope joined the urgent appeals for peace from bishops in the Middle East and called on the international community to "ensure the necessary help" reaches people fleeing fighters from the Islamic State (IS) extremist group.

Jihadists who took over large areas of northern Iraq Thursday have forced 100,000 Christians to flee and occupied churches, removing crosses and destroying manuscripts, Chaldean Patriarch Louis Sako, speaking from his base in Kirkuk.

"There are 100,000 displaced Christians who have fled with nothing but their clothes, some of them on foot, to reach the Kurdistan region," he told AFP.

"This is a humanitarian disaster. The churches are occupied, their crosses were taken down," said Sako, the leader of Iraq's largest Christian denomination, which is aligned with the Roman Catholic Church.
He added that up to 1,500 manuscripts were burnt.

The Islamic State (IS) group, which swept across much of Iraq's Sunni heartland two months ago, attacked several towns and villages east of its main hub of Mosul, the country's second city.

Among them was Qaraqosh, Iraq's largest Christian town with a population of around 50,000, and several surrounding areas that were previously controlled by the Kurdish peshmerga force.

Fleeing residents reached by phone as they tried to enter the neighbouring autonomous region of Kurdistan confirmed the jihadist takeover.

AFP could not immediately verify the current status of those towns, which witnesses said have been completely emptied of their usual population.

"Daash (IS) militants last night attacked most villages in the Nineveh plains, firing mortar rounds and seizing some of them," Sako said.

"The government is unable to defend our people, as is the Kurdistan government. They need to work together, receive international support and modern military equipment."

"Today we appeal with lots of pain and sadness, to all people of good will, the UN Security Council, European Union and relief organisations, to help those people who are facing mortal danger," Sako said.

"I hope it is not too late to avoid a genocide," he added.