Jihadist militants have taken over a monastery in northern Iraq, one of the country's best-known Christian landmarks, and expelled its resident monks, a cleric and residents have said.

Islamic State fighters stormed Mar Behnam, a fourth-century monastery run by the Syriac Catholic Church near the predominantly Christian town of Qaraqosh yesterday, the sources said.

"You have no place here any more, you have to leave immediately," a member of the Syriac clergy quoted the militants as telling the monastery's residents.

He said the monks pleaded to be allowed to save some of the monastery's relics but the fighters refused and ordered them to leave on foot with nothing but their clothes.

Christian residents from the area said the monks walked several miles along a deserted road and were eventually picked up by Kurdish Peshmerga fighters who drove them to Qaraqosh.

The Syriac cleric said five monks were expelled from Mar Behnam. Christian families in the area said there may have been up to nine people living at the monastery.

The incident was the latest move by IS, which last month declared a caliphate straddling large swathes of northern Iraq and Syria, to threaten a Christian presence in the region spanning close to two millennia.

Over the weekend, hundreds of families fled Mosul, a once-cosmopolitan city the country's second largest and lies around 15km northwest of Mar Behnam.

They abandoned homes and belongings after IS fighters running the city issued an ultimatum for Christians to convert, pay a special tax, leave or face the sword.

Families who were forced on the road and leaders of Iraq's Chaldean and other churches said Mosul was now emptied of Christians for the first time in history.

Jihadist fighters want to create a state based on an extreme interpretation of sharia - or Islamic law - and have targeted all minorities in the Mosul area.

Other groups such as Shia Turkmen, Shabak and Yazidis have suffered even more than the Christians, who have largely escaped summary executions since IS swept the region in early June.

Mar Behnam is a major Christian landmark in Iraq and a site where the local community and pilgrims traditionally pray for healings and fertility.

It was built by Assyrian king Sennacherib II as a penance for having his children Behnam and Sarah killed because they had converted to Christianity.

Ten people were killed, including a mother and three children, in a government airstrike on a militant-controlled town north of Baghdad this afternoon, according to hospital sources and witnesses.

The attack targeted the town of Hawija, 230km from the capital, which is controlled by Islamic State insurgents and other groups opposed to Iraq's Shia-led government.

A tribal leader and former army officer said the dead were all civilians, and also included an elderly couple.

He blamed the deaths on the militants for locating a base in the centre of the town.