Christians have formed their own militia to battle Isis on the plains on Nineveh, Iraq.

The Nineveh Plains Protection Units have more than 3,000 members already mobilised or awaiting training, and the backing of the Iraqi government and Kurdish peshmerga forces, reports the Catholic Herald.

More than 100,000 Christians were forced to flee Iraq's Nineveh plains for the neighbouring Kurdish region when Isis swept through the region in northern Iraq last June.

The force has 500 men stationed in towns on the plains including Alqosh to defend them from the Islamist group, with a further 3,000 in training, and is planning to roll back Isis' advances.

"The objective is to liberate their land in Nineveh Plain and to take charge of security in these areas afterward," said Yaco Jacob, a Christian parliamentarian in the Kurdistan Parliament, according to Al Arabiya News.

Along with Christians, thousands of the Yazidi minority were forced to flee Isis violence, with men caught by the group summarily executed and thousands of women and girls subjected to sexual slavery.

The defence force aims to establish an administrative area for the Yazidi, as well as minorities including the Shabaks and Mandeans.

The newspaper reports that the force is being funded by the Assyrian diaspora in countries including the US, Australia, and Sweden, and is being trained by a US security company.

A spokesman for American advocacy group Restore Nineveh Now told US News that American fundraising efforts began last June, and that non-Christians were free to join the force.

He said that Americans had so far donated $25,000 to the group.

Iraq analyst Sajad Jiyad told IBTimes UK's sister publication Newsweek Europe that the formation of the militia sent an important message.

"It's also important for the locals to send a message to Isis that they are not going to allow the demographic change to become permanent."

"The Assyrians want their land back and they – as well as the Turkmen and the Yazidis – are sending a message that: We are going to come back and we are not going to leave our villages and towns and our cultures to be destroyed,'" Jiyad continues. "We want to come back to our homes and, no matter what we face, we're willing to fight and take that back.' I think that is a positive message for the entire nation."

The Christian community in Nineveh is one of the oldest, stretching back around 2,000 years.

Since Isis took control in areas of northeastern Iraq, scores of churches have reportedly been destroyed, and remaining Christians issued with a strict set of instructions they must adhere to if they wish to remain in the area.